if your budget is not a concern, than for sure you want to be on a dedi box by yourself. i always thought the vps was a stepping stone in between shared and dedicated. i'm currently in that vps sweet spot -- dont get enough traffic to warrant my own server but i'm finding i really like the fact i can go in and change the php.ini or mysql settings. plus i'm on a managed plan now at the zone.net and it's a huge difference between the "support" godaddy provided. i'm no linux expert but i know my way a bit but its nice to just have them take care of stuff like updating apache, etc.

so if you need the raw horsepower you can go for that dedi but if you need that handholding like i do go for a decent managed vps.