Note: Both above writeups completely RAWK.
I feel compelled to chime in here, not to argue, but to add a couple of points and some emphasis. I have given and received presentations for the world's premier Powerpoint organization in terms of number and dollars - the U.S. Military. That said, there are (as noted) all kinds of things that you can do wrong, and only a few that you must do right.
Simplify, Simplify, Simplify
As generic-man notes, "less is more." There all indeed all sorts of cool toys that let you produce graphically rich slides, with tons of information; these are meant to build the handouts that you distribute after the presentation, if you absolutely must. In other words, if you are distributing a nice set of reference information for the audience to use later, sure, more information is good - they'll only be looking at it when they're trying to find something, and compact, easy to skim info-rich pages can be good.
Do not ever overload your presentation slides. Remember this: the slides are there to anchor what you're saying. They are there to remind your audience of the context of your speech. They are there to provide a static structure to what may become a discussion. The slides do not impart the information, you do. If you think slides must absolutely impart complete information, see the note above regarding handouts.
Save the Trees
There are mixed views on offering handouts of your presentation beforehand. I personally find it most distracting to have an audience riffling through decks of copy paper, and find myself annoyed at every head turned down to look into their lap. It means that there will always be someone who looks up to ask a question or make a comment who, if they had been listening, would realize that in fact that answer or comment had just gone over their ducked head.
I do find one situation where handouts can be useful. If you are going to be presenting a large quantity of information that your audience will want to take down, or if the presentation is intended to provoke discussion over your points, then it can be quite helpful (especially at conventions or meetings where folks forgot to bring a yellow pad) to offer simply a deck of paper with the slide titles at the top and perhaps two or three bullet points from that slide just beneath it. Think about distributing pens, as well. This will allow folks to easily take down notes or structure their ideas before talking, as well as make it easier for them to decipher their notes of the discussion later if the pages are marked with your core topics and presentation flow.
You're not a Graphic Artist
Really. You're not. If you were, and you were presenting, you wouldn't be using PowerPoint. Think about it. Realizing this is a good thing. There may, in fact, be graphic artists in the audience; and there are many, many more critics of design than good designers. In case you hadn't gotten it yet, this is an entreaty to (as my predecessors above plead as well) leave well enough alone, and avoid (like the plague) PowerPoint's tempting easy candycoating of clip art, drawing tools, color blends, backgrounds, and the like. Try the following: Whenever you find yourself putting something on a slide that isn't text, ask yourself does this offer the audience any additional information? If so, does it do it in a dramatically more efficient manner than if I just told them?
One of the best arguments for plain, black on white text is simply that the average presentation hardware cannot realistically come anywhere close to matching the clarity, contrast and resolution of the CRT on which you're composing the thing. It will be dark, hard to read, distracting, badly off tint, or some such, and you're out of luck. Also remember the following: LCD projectors, especially passive-matrix ones, suffer from 'ghosting' along the lines extending from displayed object's edges. A white dialog box or text box in the midst of a dark background will likely leave ghost lines extending from corners, etc. etc. Think about whether you'll be using transparencies or computer projection; if the former, you'll have to be careful with dark colors since they'll just show up as opaque, and lighter ones may not transfer well at all.
Are there places to use graphics? Sure. The most effective (in my opinion) is in the highlighting. If you have a corporate logo, or project logo, put it in a corner somewhere in a footer (never header). If possible, use nice-looking dividing lines - if you're on live hardware (projectors), a nice single-tone color faded dividing line goes a great distance to making your presentation colorful and fun - without distracting. Try cribbing elements from corporate electronic stationery's borders, or if need be, scan in a piece of stationery that has a nice line element on it.
There are mixed schools of thought on background images. I tend to use them only on section title slides, where there is no real information overlaying them; your style and mileage may vary. If you do use them, be sure to look at them on your final presentation media during rehearsal to be sure that they aren't too light or too dark!
James Bond? Maybe, but only if you have Q, too!
Remember this above all else: gadgets or gizmos are only good if they make the presentation more seamless. If your audience sees you using them, they're distracting. Always try to get RF remote mice or slide controllers over IR; you have to brandish the latter at the receiver's line of sight, and will end up looking like Captain Kirk wondering why his Phaser-I won't stop a Horta. An RF remote can be manipulated behind the lectern, in a pocket, or just discreetly down at ones' side without grabbing attention.
Laser pointers should only be used for their intended purpose: quickly pointing things out on screens too large for you to do so manually. They are bright and will wobble around, swiftly attracting eyes to your intended point; but if they remain on for to long, it becomes almost impossible to study the slide with that eye-grabbing red dot doing the samba across the screen. If you're within reach, a telescoping pointer is a good tool, especially if you need something to fidget with below the lectern. :-)
If your venue has all sorts of handy toys, by all means use them if they'll help; however, also make sure that there is someone within easy reach who knows all about how they work. Even if you have a backup, having to say "Oh, well, let's skip the video for now," or "Hmm, maybe I"ll use transparencies" or even "I guess I can use my wired mouse to click" is like a presentation death sentence. Even if they're there, please, rehearse, and make sure that the gadgets and a support person are there for the rehearsal so that you can familiarize yourself with their limits (gadgets and personnel both) before trying it live. If you must give a presentation cold in a complex environment, try to avoid using as many of the gizmos as possible; the fewer you try, the fewer chances to look stupid you give yourself.
Whew. I'm a pedantic bugger, and I'm losing the Keep It Simple, Stupid! game myself. One thing I always tell myself before the presentation: They're here to listen to you, not read the slides or get a demo of Powerpoint. They could do either of those from the comfort of their cube.