I tried Kubuntu, and over all, it very nice except as Gowater said the sudo thing bugged me. But I took it off and installed Mandriva instead because CUPS and Samba don't work. I spent days trying to share my printer with my wife's notebook, and never did get it to work. With Mandriva, it took less than 15 minutes to get my Brother MFC printer online and shared with WinXP.
Other than booting problems caused by the "resume=" option, I really haven't had any problems with 2007. So like always, it depends on what your going to do with it.
Oh, I wasn't able to get my WinTv PVR150 card to work with Kubuntu. Haven't tried yet with 2007.