I guess it depends on what we’re talking about. The OP mentioned gaming. Is Tom’s Hardware a good enough cite?
http://www.tomshardware.com/2007/10/17/parallel_processing/page6.html#3d_game_benchmarks
Now, can you give me a cite where it shows gaming speed increases?
Granted, squeegee is correct that I’m behind the times on my information depending on your focus. The current on board RAID do show nice gains with drive intensive operations. Going back in time, the first on board RAID controllers really didn’t give much except a loss in MTBF and the ability to span drives. I really don’t want to go on a rant about RAID, so let me just say that it has its time and place. For someone who wants a gaming system and doesn’t feel good about building their own, it’s neither the time or the place.
I also agree with squeegee about investing in a very good flat panel display. I also recommend a nice set of surround speakers. They can really enhance your gaming experience.
The bottom line to me right now is that it’s a great time to buy a mid to high end system, but it’s a terrible time to buy an extreme, bleeding edge system. Nvidia (the current leading video chipset producer) is in the process of making their high end video cards obsolete. ATI (the other major video chipset producer) can’t compete on the high end. You will see better, faster cards from Nvidia in the next month or two. As a bridge, they have just released the 8800GT chipset which has incredible value compared to what was available for the previous year. It’s only slightly slower than the current bleeding edge cards at less than half the price.
Processors are in a similar situation. AMD is lagging behind Intel on the high end. Their new high end processor (Phenom) is underwhelming in its current state. I expect it will improve in time. Intel is in the process of releasing a new series of processors based on a 45nm core (Penryn). Most of the new Penryn processors will be hitting the market in Q1 of 2008. This is leading to some good values if you’re slightly behind the bleeding edge. One of the current favorites is a Q6600, which is one quarter the price of a bleeding edge processor.
RAM is another example. DDR3 is coming, but at extreme prices with no current real world performance gain. Let someone else buy it. DDR2 is very cheap at the moment. That price will go up as manufacturing is switched to DDR3. If you are buying a new rig now and spending the money the OP is talking about, there is no good reason not to go with 4G, just stick with DDR2.
Since we’re now in IMHO, to the OP I would recommend either waiting a few months if you want a bleeding edge system or buying something mid to high end now and investing some of the rest in a sweet monitor and sound system. YMMV.