Used minis are also a pretty poor lot because they're just not depreciating all that fast. Even the pre-Intel ones aren't going for much of a discount. Buying one used just isn't much of a break --not enough to cover getting a warranty and the latest OS that I'd get with a new Mac.
Now then, I just noticed Micro Center has G4 minis on clearance for $450. That's not a huge discount from the Intel mini's price of $600, so my question is this. Given that the sum-total of my work with this Mac will be the following:
1. Porting my games.
2. Ensuring that my web-games look right on Mac browsers.
Would I be better served getting a $450 G4 Mini or a $600 Intel Mini?
Also, what's a good KVM switch that'll let me use the Mini with my existing Dell 20-inch monitor(s) and USB mouse and USB keyboard?
The G4 mini is a solid machine, but the price is not that much different from the low-end Intel machine they are selling.
Shell out the extra dough for the Intel mini; you'll get much better graphics performance and the ability to virtualize and dual boot with Windows in case you need an extra Windows box. You not only get a new OS X version, but an improved version of the "iLife" tools that come with it (Garage Band, etc) and a cool little remote for use with their Front Row media centre interface. And dual channel RAM, which really improves overall performance (though you may wish to upgrade this later, I don't know off the top of my head how much RAM the low-end Intel Mini ships with).
It should work with almost any KVM switch; you can buy PS2/USB adaptors that will work fine with a cheap switch like I have. IIRC, it plugs into DVI but comes with a VGA adaptor in the box.
Give me a PM if you have any more Mac questions, but the Intel mini is substantially faster and a nicer rig overall.
Oh! Almost forgot: If you subscribe to Apple's Developer Program ($100/yr) you can get a substantial hardware discount along with it, as well as beta versions of the new tools and operating system stuff as it arrives, and access to Apple's software testing labs. It may be worth your time and money.