Currently quad core is still relativly less powered for gaming (AFAIK). This because games are written with not all that many threads. Therefor the speed of the cores you have becomes more important (ie 2 faster cores can perform more then 4 slower cores).
Think of it of having 2 factories to produce for example bottles of orange juice. Say you get an order for 1 orange juice bottle (crappy order I know
). That means you have no use of the second factory because you only have on thread (only one bottle to make) (unless one factory of course can make the bottle while the other can make the juice, aka you have 2 threads). Now if you get an order for say 4 bottles, that is something you can handle quicker as you can now use both factories (in theory you can be done 2x fast). If you had 4 factories you could do that order in 4x the speed as when having one factory. The problem however remains, which order are you getting.
At which point in time we are, I'm not sure, but I do know that 2 core chips are cheaper and clock better / higher. As for your budget/brand question: Why not build your system yourself? Second how long are you planning on working on the system (for gaming or typewriting and such). Personally would go with the quadcore Intel proc (but that is partly because I am unsure how the AMD will perform, I have the feeling it is quite old...).
Acer isn;t too bad though (not to fond of them myself but I know several of my friends who have Acers and are fond of em)
BTW if you are going to buy these for gaming, forget it
:
Integrated NVIDIA GeForce 7100 / ATI Radeon 2100
