"I think pirastros are the really expensive?"
It really depends on the set (I've been doing a ton of research since my last posting). Some Pirastro sets are fairly cheap compared to the others (under $50 a set). They also make higher quality synthetic core strings up into the $80 range. With exception of Eudoxas, the Pirastro gut strings are normally around (or at least) $100. So, yes, they can be very expensive.
fearfaoin, that is a very good and popular set of strings. My last set (which apparently was not steel!) was that arrangement, chosen by the luthier who did repairs on my violin. That Pirastro Gold E is really nice, especially way up in the high register.
Ian, restringing really isn't very difficult. You just have to be mindful of the bridge (you want to try and keep it straight, not tilted). It's also best that when you wind the strings on the pegs, they looks like coils on a spring and not overlapping itself.
Just for the sake of saying (I'm not endorsing them, just passing on what I've found) - I've heard very good reviews from classical pro's on the Larsen Tzigane strings, which I intend to try next. They're supposed to be very resonant (and loud), complex, low tension (but still relatively thick in diameter), and responsive. From what I gather, they play and sound very much like gut strings (namely Eudoxa), but are more stable, and maybe even more responsive. Sounds like love!
