Would I be better off getting a $400 pair of active monitors or a $400 pair of passive monitors that run off of either a 10 year old Technics receiver or OLD 75 watt-ish Crown amp? The Crown amp's not bad, but it needs work. I guess what it comes down to is whether an amplifier matched to a speaker with cheap parts is any better than a speaker with slightly better parts running off of an amp that has neither been matched to the speaker nor is particularly good.
I'd answer the second part on a case by case basis.
In answer to the first part, I'd be tempted to say that active would be better since the system will be designed to work together but OTOH you can use what you have now and get a better amp later, which will allow you to get better monitors now.
I got a pair of Tannoy PBM 6.5's for $100 and they're great.
I'm not saying that these are the exact monitors you want, but for example:
If you are buying new, get the active speakers. The key is the cross-over. You can do a lot of filtering for cheap on the line-level side. Good passive cross-overs can be expensive enough that an active cross-over and two amps are about the same price.
Sometimes you get lucky with a mid/woofer and tweeter combination that sounds great with a fairly simple passive crossover (like the ST6).
The best bang for your $400, since you have an amp, is a used passive pair. They aren't real hip right now and you can pick them up pretty cheap. Don't forget the mid-range semi-audiophile used speakers either (like NHT, Celestion, B&W, Boston Accoustics, and so on).
Yeah, those Tannoys look good (nice and cheap on ebay).
Anyone have some info on those? I found a little bit about them online. Seems like they'd be a great deal, especially if I can pair them up with a better amp down the road.
Do these have any harshness on the top end? Are they shielded? I have an LCD monitor (it's an imac) but putting unshielded speakers near hard drives and other electronic stuff makes me nervous...