Will HD4650 have the juice to game with 30+FPS if coupled with a nice overall rig?
If coupled with a nice overall rig, the 4650 is going to be the weak link. Although I suppose it all depends on your definition of what a "nice overall rig" is. Which is why it would help to know what CPU, RAM, etc. you are going to use it with.
The short answer is: Yes, as long as you're not doing super-intense gaming like Crysis, a 4650 is going to do OK at lower screen sizes like 1024x768. Not great, but it will get the job done. If you move beyond that, at least a 48xx series is recommended, and personally, I'd do that anyway if it was my machine.