I agree with the Windows 2000 UI being great, but Windows XP ran better for me.
To get the best of both worlds I ran a spare copy of Windows Server 2003 as my "daily driver" on a Thinkpad back in the early 2000's. It had the Windows 2000 UI with the behind-the-scenes updates that came with Windows XP. Most software that installed on XP installed fine on Server 2003. It was nice.