You can make FLAC files play and the tags and cover art work quite well (track length and year don't work and cover art doesn't show for tracks other than the first one, or sometimes two, of an album). The following post should get you started if you want to do so:
FLAC playback in Vista?
I'd say unless you need to use FLAC, APE or whatever for some reason then go with WMA lossless - you can always convert to another lossless format in the future. I have a media player that plays FLAC but not WMA lossless so I use FLAC.