At a glance Jughead is many things; a woman hater, a burger lover, a mooch, and a good friend. Even those few attributes are more than most of the other Archie characters have. But Jughead is a lot deeper than that. He has motivations that are as real as any person walking down the street. Jughead is a deep and complex character. It would take an entire book to explain him (alas all I have is one node to do it in).
Jughead suffers from recurring bouts of depression (although they never use that word in the comic books). All those years of playing second fiddle to Archie have done something to him. Because of this, Jughead will often try to outdo Archie (often succeeding, because after all, Jughead is a lot smarter than Archie is). But deep down he feels inferior to Archie and Reggie both. He will often sabotage himself when he feels that the going has gotten a little too rough.
The character of Jughead has a very weak sex drive. He simply isn't interested in women for the most part. He goes so far as to call himself a woman hater. Several issues from the mid 1960s show that Jughead is a member of a "Women Hater Club" (which is composed of a bunch of 12 year old boys, and Jughead). Jughead is relentlessly and comically pursued by Big Ethel (a very unattractive girl). From time to time she will catch him, and force him to go on a "date" (that she had already planned out). Jughead will usually pout or try to escape when this happens. There is also a large group of much more attractive girls dedicated to the pursuit of Jughead (The United Girls Against Jughead). They hold meetings and often try to lure him into a trap where they can seduce him. However, this never works out. Not to say that Jughead has never fallen for a girl; he has, several times. However the girls that Jughead does fall for are few and far between (and are usually from out of town). The stories of Jughead's relationships are very rare though (and the girls never become regular characters).
The beanie that Jughead wears is more than just a hat. It is both his symbol of power, and his cry for attention. On the few occasions when Jughead lost his hat, he would become very depressed, anxious, and self-concious. Jughead sees the hat as part of himself. Without it he is nothing. In a few of the alternate reality stories, Jughead's hat would become a source of all sorts of powers (ranging from flight to time travel).
Jughead's family doesn't make as much money as most of the other families in Riverdale. Because of that, Jughead rarely has money (even when his friends do). Jughead's lack of money is another reason for his bouts with depression. This has caused him to become somewhat of a mooch. Archie often ends up footing the bill for a lot of the things that Jughead does. But Veronica has spent more money on him than everyone else put together (several stories show Ronnie sending Jughead on "food trips" and catering expensive dinners for him, as birthday and Christmas presents).
The greatest love of all for Jughead is food. He loves all sorts of food (but especially hamburgers). Jughead can eat more food than a man three times his size. His most frequent place to eat is Pop Tates (or the The Chocklit Shop as it is usually called). Poor Jughead is forever in debt to Pop Tate for all the burgers that Pop has given to him over the years (when Jughead was once again out of money). The second favorite place for Jughead to eat is the kitchen at the Lodge mansion. But his feasts are usually interrupted by Gaston (the Lodge's Chef), who will chase him away (while screaming at him with a cartoonish French accent).
All in all Jughead Jones is quite an interesting character. Dannye has compared him to Maynard G. Krebs. That one real person in a sea of otherwise one dimensional figures. For me Jughead is what the Archie Comics are all about. The other characters are only pale shadows of the depth that Jughead exhibits.