The good, general advice is to go and listen to a bunch, and make the decision with your ears.
Now, having said that, there are a few that I personally think are worth looking at in that price range. If you must buy new, then the Event 20/20bas monitors routinely do well in shootouts, and come in around $700.
The Mackie HR624's should run you about $1000.
If you're willing to buy used, that changes the game. My preference would be the Mackie HR824's (ebay for around $750), but you could also look at used Yamaha NS-10's (real polar opinions on these, you either love 'em or hate 'em),
Genelec 1029's, KRK V8's, etc.
Definitely worth hearing these all new at your favorite shop. Bring along music you've mixed, and some reference CD's you know really well. It should help you discern what a given speaker's strengths and weaknesses are. I've been told that you can get some really good mixes from a pair of $500 (or less) monitors.
-mg