If you truly want to be a mac gamer, you need to buy the best hardware to keep up. It is the same way as the pc world; how many hardcore gamers keep the same system configuration for more than 6 months? Not many.
it's been that long since Apple updated their fastest products.
The problem is that there are so many things that change QUICKLY in the gaming world. One day, a 9600 is plenty, and 2 months later, you might need a 9800 XT or something, just to get games to play at your LCD's native resolution with most of the features turned on. There are how many options for mac gamers? almost zero.
I could look right now at pricewatch.com and pull up 20 different versions of the 9600 and 30 different versions of the 9800 that all have different features and target markets. There are those with overclocked cores built in, those with passive cooling for silent operation, those with huge gaming bundles, those with dual DVI out, those with TV cards built in, those that have less ram, those with double the standard ram, and they all come in at a variety of price points. Serious gamers often want multiple hard drives and multiple optical drives. The G5 case seriously deters this.
You have to understand that, as a serious gamer, I do spend a lot of money on gaming stuff, but i spend it in small chunks. The only viable "gaming" upgrade I could buy aftermarket for a G5 is the 9800 Mac SE, and it's 500 dollars. that's how much my whole computer cost before the graphics card.
I spent 700 and got a 9600 Pro 128, 2x120GB SATA drives, a 500 watt powersupply in a slick annodized black aluminum case (with some custom lighting effects that aren't even tacky), a MOBO with 7.1 surround, digital audio input, 6 UBS 2.0 ports, 3 FW 400 ports, overclocking protection, 6 ultra-quiet fans, 2x512 MB Geil Golden Dragon PC 3200 RAM, and an Athlon XP 2500+ overclocked safely and without any "tinkering" to just short of XP 3200+ speeds. For 700 dollars.
I've since added another stick of golden dragon and a wireless MX kb/mouse combo. I'm considering upgrading to the 9800 XT whenever the next card is released, depending on what the benchmarks show me.
The fact of the matter is, I have a KILLER gaming rig that runs evverything I throw at it full speed for well under the entry point on an iMac. I've tried some photoshop filters on huge files, and thanks in part to the RAID 0, it performs just slightly behind my dual 2.0 G5 in practical everyday editing of a 100-200mb layered image.
I have no doubts that you could force a Mac to play some games, and that you could have fun doing so, but until the hardware market opens up for them, I'm sorry, progress will always be slower and more careful.
I must say, though, that i find it ironic that IBM has for all intents and purposes saved the macintosh.
Sorry for the ranting. I just want to be able to pop the hood on my 3000 dollar G5 and make it run Halo to a comparable level that my 700 dollar XP2500+ does.