What PC games at what resolution? something like BF3 or something like Minecraft? Both of them have integrated graphics, I really can't give advice untill I know what games u r planning on playing
EDIT: What's your budget?
For video editing... It'll work, but will take its sweet time doing it.
For gaming... not much going on there. You will need to add a GPU and, in turn, a new PSU to handle the increased power requirements. That'll blow the budget and make you consider building a PC to meet your needs.
Which is the better value? Probably the p6-2035uk. The CPU upgrade and larger HD on the p6-2046uk isn't worth the extra cost. The other parts are all the same...