Really? On most computers that I used, 98 and 98SE froze frequently.
Not to forget the dreaded "Windows is shutting down" screen that used to sit there for hours on end, and Windows would never actually shut-down. 98/SE was terrible for hanging shut-downs, and Microsoft never worked out what exactly was making it hang. The so-called "patch" did not work at all, it just disabled the fast shut-down option which didn't help.
Unless you use a ton of old software, 2000 is virtually useless as hardly anything installs or works. You need a good web browser, and IDK if Opera or Firefox still works with 2000 or not, but Chrome doesn't and Safari doesn't either. I know there are more than four web browsers out there, but if none of the new IE alternatives work in 2000, you can't browse the modern web in IE6 nowadays can you? Chances are your software that works on 2000 will work on XP, so I don't gwt why you don't just use XP?
The good thing about old unsupported OS's is that the virus and mallware makers do not support it anymore either.
Not to mention support for 2000 was dropped about a year ago, and as it is based on the NT kernel which all later versions of Windows, expecting Me, are using too, this does not mean it is more secure as it's old. You do know underneath the hood, 2000 and XP are virtually the same right? Therefore, if a virus works on XP, it should work on 2000 too, it's just it depends on how the malware is delivered through the web or whatever, as it may require something like Silverlight which of course does not work on 2000. Only thing is, you are better protected on XP as on XP (or any newer Windows OS), anti-virus manufactures still support it. You try finding an anti-virus for Windows 2000 that doesn't slow you down considerably, the only one I can think of is ClamWin, and if I'm honest, that's a bit rubbish. Windows 2000 is differently showing it's age.
I never had problems with any of the Win 9x or ME releases with respect to reliability
Wow you must have been the only person in the world to not have stability problems with Me! That OS was dreadful, honestly the worst thing Microsoft has ever made. As far as 95 and 98 go, not as bad as Me, but not great either, remember 98 to be quite bad on the stability side of things. As you say, hardware manufactures often didn't bother to re-code drivers for Windows Me, they just used the 98 drivers, but you can't say every single computer running Windows Me at the time had bad RAM, Me was just prone to blue-screening, due to RAM most of the time, but not how good or bad your RAM was, it was about how Me handled the RAM.
Running a newer OS like XP on old machines with limited RAM ceilings is not much fun, but the old OS make those machines usable for real work (just use older apps).
Depends what your idea of "limited RAM ceilings" is. XP will run fine on 384MB RAM, or maybe even 256MB at a push, and it also depends what you install on it. If you only install the programs you need on XP with half a gig of RAM, it runs fast, but if you fill it with junk software you got free with computer magazines from the late 1990s/early 2000s like my Grandad often does, it runs slow. Yes I do agree with you on using the older applications and an older OS to make working on these PCs easier and smoother and faster, but seriously, what sort of computers are you running on if it cannot handle Windows XP?
I still don't really get why you want to use an old, outdated and somewhat slow (especially boot-times!) OS, but if it makes you happy, I'm not stopping you. I'd recommend XP anyday of the week over 2000.