In reply to cfer:
I don't mean to state the obvious, I've got no idea how much you know about audio kit. The thing to consider with audio is that one of the main factors in both cost and quality is the amplifier. The signal from the amplifier (unlike ethernet cables, wifi, bluetooth, USB or virtually anything else you encounter in your daily life) is not just transmitting the audio data, it's actually physically driving the speakers, hence the need for the amplifier. The more speakers you drive off one amp, the more power you need, most home amps only support 4 speakers, so you could potentially do two rooms with that with wires running through the walls or some such.
Modern multi-room wireless systems necessarily have an amp in every unit. You may think of them as 'wireless speakers' but they are really wireless amplifier and speakers in a single box. If an easy, scalable, moveable (i.e. when you move house) multi-room system is what you want then it's hard to beat this, but if sound quality id what you want, splitting your money across lots of little amps is unlikely to give the best result.
I had the same choice and went with a traditional amp and speaker set up in one room (amp is a Denon PMA-720 - bought on ofer for £100) and speakers are Celestion floor standers (about £70 off ebay). Sound quality is ace and you'd struggle to get wireless in even two rooms for that price.