Yes, iTunes can coexist with Windows media--poorly. Here are the limitations:
1. iTunes knows nothing about Windows 7 Libraries, and will not monitor library folders for new media; you have to manually import media into iTunes, and reimport as necessary to get your media to show up in the iTunes library.
2. iTunes will not directly import WMA files--but will transcode them to AAC, making duplicates along the way. WMV files are not supported at all.
3. You don't really have to worry about iTunes downloading new cover art. In fact, it's basically impossible to get cover art through iTunes for any files you didn't purchase from Apple. You'll have to download cover art manually and import that into
the files yourself.
4. There's work involved if you want iTunes and Windows to have a common view of media stored locally on your computer. Since by default iTunes puts its own media library inside your My Music folder in Windows 7, whenever iTunes transcodes files or
makes copies, these new items will show up as duplicates in Windows Media Player, Zune and WMC. You either have to move the iTunes library outside of your Windows 7 library altogether, or point your Windows Music library at the iTunes media subfolder
rather than at /users/you/music
The good news is I have not found a problem with pointing iTunes at media folders stored on Windows Home Server. If you keep all your media on the server you should find it relatively easy to keep iTunes and Zune in sync. Just remember that iTunes
won't find new files that you add to your media library on its own. You have to manually import them.