You can use Media Monkey in MSC mode, sync with it, playlist, etc.
http://www.mediamonkey.com/wiki/index.php/About_MediaMonkey
I know very little about Replay Gain. But if I understand correctly the part about Media Monkey here:
http://wiki.hydrogenaudio.org/index.php?title=ReplayGain
then MMonkey writes the Replay Gain information into the tags of the files themselves. So I would think you could do the Replay Gain thing with MMonkey, and then copy-paste the files via Windows Explorer or via MMonkey.
By the way, you mentioned Winamp. You can just make the unwanted modules (like EQ, Media Library and Video for me) disappear by right-clicking on the top of the window and un-checking them
