Is this one of them "my dicks bigger than you're dick because my computer is OBVIOUSLY better"? :P
Of course it will last you, Phenom's and indeed Quad Core processors are not even needed in this day and age as the games just don't touch the surface of there speed, so yes that will last you at least 2 years or until the next gen comes out.
The RAM is fine the only improvement that could be made and I don't know if you can I would have to look at you're MOBO spec's but it might be able to support 8GB, which might be useful if you're on Vista and playing heavy games.
The ATI HD 5750 1024MB DDR5 is a excellent card, if memory serves it won some sort of award for being one of the best high end budget cards, due to its small-ish price tag, I would say that within the next couple of years when next gen is released you might need to change it, but for that matter half the population will. But for MMORPG's/Aion and such it will burn them, and same for a lot of the HIGH end games in the current market.
Quick side note: if you do intend to buy a Phenom, and you want to play stuff like WoW for example on it, you might want to look on the Internet for Quadcore support for WoW, as like I said most games in the current market are not actually supported by Quads.
