I've been using WMP to sync to my Creative Zen since I bought it a year ago. It worked fine when my collection was still smaller than its capacity, but that's no longer the case, and I can't find any way to specify which music should be synced/not synced. WMP's sync by alphabetical order is an unacceptable option.
What I think I want is something that would show my collection organized by artist/album/song (with file size info) in a treeview with checkboxes that saves my selections so I just have make adjustments as needed with new albums instead of having to rebuild my list from scratch every time.
Trayplayer has a UI similar to what I really want for a playlist builder; but aside from the run once per boot register nag it doesn't appear to work well with win7-64. It can't embed itself into the win7 taskbar and the only way I can open it is via hot keys.