Someone got me ranting about these. Anyways here's my recommendations. For more useful Japanese, see the links (scroll to the far right if you have a small screen and/or resolution.
This one will let you do romaji, but you gotta remember to click the box. I recommend starting to type in hirigana asap anyways; it helps out more than you can imagine.
This one is intended for Japanese people who are trying to figure out american idioms and such. But it works even better for us. Now you can look up crazy phrases like "TGIF" (Yareyare yatto kinyobi da!). And it also works as a good dictionary and example sentence finder
But Clay, ALC uses kanji! Well, I recommend getting Firefox and the rikaichan plugin. Wiki firefox if you haven't seen the light, the wiki Firefox plugins too. BTW, Rikaichan is a dictionary in it's own right, and a powerful one at that,just don't forget to download the appropriate dictionary file too, or it's useless.