Keep some things in mind...
1. Are you capable of running without a control panel? (some VPS' come without such luxury, the cheaper of them anyway)
2. How much ram will you need dedicated to your site? Burstable? (we use like 384 dedicated ram and 1024 burstable)
3. How much disk space will you need? (I host several of my sites on one vps account, so i need about 10gb)
4. How much BW do you need? (200gb is about average, some go much, much higher)
The list goes on and on and on lol...
