Problems using my Airport Extreme Base Station with an external HD as an iTunes library I have my entire music collection on an external HD which I connect to my network through a direct USB connection with my Apple base station. I'm finding that iTunes struggles to load the library (43,000 files - some of which are hour long podcasts/mixes etc) and I've also purchased TuneUp to tidy up my music collection, but given that iTunes struggles to load in the first place, this avenue isn't even worth considering right now. 

Does anyone have suggestions on how I might improve the setup? What connection between the base station and the external HD would give the best result? 

It isn't practical to connect the drive directly to my PC as I'm using a laptop for my main machine, plus I'd like for the setup to work when I'm not at home so my partner can use her iPad or iPhone to browse/play the music.

UPDATE: The iTunes Library is on my machine running Windows 7 as opposed to on the external HD.
You've done the most important optimization available by placing the database files (the iTunes library  files) on the local drive. If you had that on slow storage (and Airport Extreme is in the slow category as far as network storage) then I could see you having slow launch times.

Even a library with 70,000 items stored in it should only have an iTunes Music Library.xml file that takes about 120 MB of space which should load in less than 10 seconds unless your PC is really bogged down with other tasks on the CPU.

The actual size of all the media doesn't affect the application launch time as it only has to parse the library files and not check each and every file before you can start using the program.

I would look at tuning up the PC or speeding up the filesystem where the library files are and see if that results in better app performance.