Did not mean to dissuade you from any NG Amiga purchase by any means - as I said, I myself use a SAM as my sole Amiga lately. But I simply couldn't recommend one as a PC replacement unless your needs were rudimentary to the level of "I check my hotmail and listen to a few MP3's and that's all I need a computer for". I love my SAM for what it is, but a PC replacement it simply isn't.
My recommendation, honestly - keep your eyes open for a PPC Mac that is compatible with MorphOS. Heck, around my parts people give the things away. Download MorphOS demo, give it a whirl and if you enjoy it it can be registered. If not, you still have a low cost Mac running OS X that is capable of pretty much anything you need it to do. Or run Linux on it if you dislike OS X or MorphOS, or simply sell the thing off. Mac Mini's can be had for $100 any day of the week.
In a perfect world, Hyperion would port OS4 to the old PPC Mac's and we could all explore OS4 at a far lower price point, but that won't happen anytime soon. It's a terrific OS that is locked to extremely costly hardware at the moment.