I never tried to use Jaangle alongside another media player, so I'm curious about any possible file association/album art display problems (in W. Explorer), but indeed, you're certainly welcome to try or use both.
As I said, Jaangle is simply a "media player/organizer". I do not have any music file types associated with it for Windows, since I have Winamp installed as my default music player for all music types.
So, Winamp icon shows for music files in Explorer and any other Explorer-like programs (e.g. Free Commander), double-click on them and Winamp launches, etc. Jaangle is not at all involved in Windows defaults (for me, anyway).
To use Jaangle I simply open it, and then use it. If I want to play music with Winamp while being in Jaangle I simply right-click on the selected music files and hover the mouse over "Advanced" and then click on "Play (external player)" from the flyout sub-menu. Otherwise I just play the selected music files within Jaangle itself, which is perfectly acceptable to me.
As far as album art in Windows Explorer, I do NOT have any "music library" definitions. Don't use Windows Explorer... I use Jaangle. All of my high-quality 500x500 album art is present as "cover.jpg" files in the album folders (my collection is organized \Music\Artist\Album), and this is understood perfectly both by (a) Winamp, which displays these images in its Album Art window when any music file in that folder is played, and (b) Jaangle, which discovers the presence of these "cover.jpg" images during the analysis of the "music collections" (i.e. folders) I've defined. So when an album is selected in Jaangle, this same 500x500 high-quality "cover.jpg" album art is presented.
The exact same \Music\Artist\Album structure, including "cover.jpg" in album folders, is also duplicated onto my Cowon J3 portable music player. Again, the high-quality 500x500 "cover.jpg" is presented on the J3's screen (resized by the J3 to 272x272).