My recommendations for retrogaming
For Dos games try DosBox (http://dosbox.sourceforge.net
I think IMHO it's the ultimate Dos Retro utility. The combatibility is great, and there is a large community, build around it. (And since it's open source, it might be ported to Classic Amiga OS or Morphos).
For Win 95/98 games, a dual boot system with WinMe and XP is great. Although WinMe is infamous for it's instabillity, it is very compatible with newer hardware, and I found out that it's great way to play 98/99 games. And if you like to play Glide games, some very good Glide Wrappers:
) and Zeckensack's Glide Wrapper (http://www.zeckensack.de/glide)
I used the above software configuration on a PIV 2,4 , with 1 GB memory, and an 6600GT video card. Since I do not have a lot of space in my house, to build a dedicated retro machine, I use one machine for gaming, with multiple software configurations.
Now some remakes:
Knyte Time http://retroremakes.com/forum2/showthread.php?t=6757
A Bards Tale inspired game : http://www.battlephase.com/warrior
A much updated Doom : http://www.doomsdayhq.com/
Gl Frontier http://soul-less.pwp.blueyonder.co.uk/
GL Frontier First Encounters : http://www.geocities.com/kolijoco/
Last but not least, for anything about retro remaking http://www.retroremakes.com/