Just to clarify... my media machine doesn't have ANY mp3's on it, so I'm looking for the best way to serve files to it and keep the library in synch without having to run a file import on it whenever I add new stuff....
I was in a similar situation... my HTPC was connected to a file server via 802.11b (and I was getting about 8 Mpbs data throughput). At first I was sharing the same library file ('cause I didn't want to have to keep two libraries synchronized). The only requirement was to put UNC paths in all the filenames (i.e. \\workstation1\d$\Music instead of D:\Music). I could have just mapped a drive on the HTPC, but I had some media on the C: drive, and there's no getting around that!
This setup worked OK for a while, but for some reason, I was getting poor performance with browsing videos - the icons took a long time to generate and I would get occasional crashes. I tried using Media Server, but I found that it didn't want to actually stream the video - and it takes quite a bit to download an entire 600 MB file at 8 Mbps (best case) or less than 1 Mbps (worst case).
So... I broke down and ran a Cat5 cable to my HTPC and haven't had any trouble since... though I stopped "sharing" the same library. MC isn't made to allow mutliple access to the library file and I was having occasional glitches in the database (nothing serious). So I'm not just doing an export of the main library file and importing it into the HTPC library file. I do it about once a week, which isn't too much of a hassle.
Well then, I guess I'm saying that I'd recommend against sharing the same library file and instead, export/import (or just copy the actual library file itself - which could probably be done with a scheduled OS event). Media Server is an attractive solution, if the performance meets your needs. Have you tried it?
Scott-