The V series is more accurate overall. Better clarity over all the ranges, better components. The Rockit series sounds muddy to me. I picked the passive ST-6's. They're basically a non powered V-6, need to use your own amp. They're absolutely fantastic though. Highly recommended.
Look at M-Audio BX-8's.
KRK ST's or V series.
Alesis series, you choose.
Right there are some great choices, that you can hopefully squeeze into your budget. You will not be dissapointed. 🙂
Peace