I'd have to throw my vote to ME as well. Finicky little monstrosity.

Having said that, I've got a machine at home running ME on an Athlon (or "the AMD Hotplate," as I call it) with 256M ram, and which actually provides a reasonable home for JRun4, ColdFusionMX server, probably a dozen or so compilers including some bulky IDEs like VC++6 Pro and C++ Builder 5 Pro, Apache 2.x, Perl, PHP, mySQL and probably a few other things I've forgotten, but which a rational person wouldn't try to run under ME.

While "stable" might be too strong a word, it works better than I'd ever have hoped. The compilers I suppose aren't too taxing (even with ME definitely not being a developer's OS), but the web and app servers are a pleasant surprise. I've never had a single problem with any of them, and as time goes on I'm using that box more and more often, even for serious stuff. I do all my schoolwork on it, C++ for the most part.

The only real problem came from Adobe Premiere 5, which would run for an average 45 - 90 seconds before doing a complete face-plant. Oh well...it's just an old toy, and I'm not Spielberg, after all.