An amusing fact from history:

Judas (or rather the Hebrew equivalent, Judah) was actually a very popular name in Israel of old, perhaps because of the Judas Maccabeus of Seleud-ass-kicking fame: The Seleucid emperor Antiochus Epiphanes had proclaimed himself to be a god (Zeus, in fact), and he claimed that he - and Zeus - were the same god as that of the Jews, YHWH. Antiochus then erected altars to himself in the Temple and outlawed Judaism. Judas Maccabeus and many of the Jews were understandably irritated, and went on to rebel with the intent of getting medieval on Antiochus' ass.

At any rate, despite dying before the whole matter was settled, Judas Maccabeus has gone down in history as being a spectacular hero (one of the nine worthies, in fact).

Presumably, the name fell out of favor somewhat after the late unpleasantness with that Iscariot fellow. . .

Grave mistakes (errata):

1. Thelady is absolutely correct in her comment about The Temple and syangogues. I have corrected it in my writeup, but in a previous form, it did contain the error she has mentioned.

2. She is also quite right in Judah/Yehuda/Judas being the name of one of the Twelve Tribes of Israel, and hence was probably always a common name. However, after trying to remember where I heard the comment about the popularity of the name Judas, it hit me: it was a passing comment in Asimov's Guide to the Bible, in which he mentions that "It is very likely that the name Judas Maccabeus made the name Judas Judah so popular among Jews in the following centuries." A quick web search has a few other people mentioning this. It seems, therefore, that either A) this is all an urban legend (of the least urban variety) or B) my write up was correct in Judas (Judah) becoming, as I said, a very popular name in Israel in the wake of Judas Maccabeus (but, as I mentioned, flatly wrong in other respects).