The cynic in me thinks that by the time OS4 is fully released, then someone will have merged the PPC-JIT code from QEMU or PearPC into UAE and itix could compile his OS4EMU as a 3.9 application to make use of the emulated PPC.
An Athlon64 4000+ with PPC-JIT would p!ss over any current A1 available.
See, now doesn't native code look all that much sillier? That's why I liked the idea of DE so much. Since I started working with Perl, PHP, and Java, I really don't want to go back to native code.
Anyway, these days you're either Mac, Amiga, or PC, since everything else works on PC hardware. If you want to use classic Amiga software, either a 1200 or a WinUAE PC will do great. If you want something more substansial, like any of the various PPC accelerated Amiga programs, you'd be better off with a Windows box where Internet Explorer has been immediately replaced with Firefox. Plenty of Linux software is available for Windows that replaces many of Microsoft's braindead tools, and XP is a lot more stable than people give it credit (with IE disabled, that is).
Also keep in mind the limitations of Amiga web browsers. The world is using a lot more CSS, DOM, and [advanced] Javascript now that Mozilla is getting a major following.