New PC, Win98/ME/XP dilemma

I’m planning to purchase a new gaming PC, but many of the games I will be playing on it are for Win95/98 and are DOS-based games (i.e. older Master of Orion and X-Com games). I know that Win98 can be a bit twitchy with the newer 2+GHz CPU’s and 512+Mb RAM. I also know that XP is NOT DOS-based and can prove difficult with DOS-based games. Should I be able to run older DOS-based games in WinME? Or should I set up for dual-OS with Win98 and XP? And if I do use dual-OS, should I look for a PC with less than a 2.1GHz processor and less than 512Mb RAM? I don’t want to spend a lot of money just to find out I can’t use my new computer the way I planned. Can someone please help?