Because your parents are obviously going to try and steer you away from the Mac, you need to take matters into your own hands. Save about $300 and get a decent used G4 Powermac off ebay (Dual-500 Mhz up to maybe single processor 773 Mhz at that price). Or save $600 and get a mini and a memory upgrade. I would go with the G4 Powermac if it were me for lots of reasons: upgradeable video card, room for lots of ram, option for various PCI cards, upgradeable processor, easier to use dual-monitors, among others.
Sure, the older machines won't run the latest games, but for almost all other tasks, the machine will feel zippy enough (edit--you also will have trouble with multi-track audio recording and video editing--both will be slower, and somewhat limited)
If you can't use ebay, consider finding a close friend who will use ebay for you (preferably your parents unless they would even nix that--if so, forget it until you move out)
I use an old Mac for financial reasons, but rarely do I feel slighted because my Mac does almost everything I want it to do quite speedily. I even was able to play Myst IV on it. Myst V, however, is out of the question due to my slow processor and old video card.
Keep also in mind that technological wizardry does not equal fun in computer games. There are MANY fun games that will run well on my old computer, or any G4 Powermac. I have at least 50 CD-rom games, and several hundred more shareware/freeware games.
Good luck. It really is better over here.