I bought a secondhand Yamaha reciever capable of a 5.1 system (RX-V373) and a pair of old Bose Interaudio 4000XL I got for relatively cheap. Currently I'm looking for a subwoofer too, and I would add three more channels in the future.
The Bose, I thought about moving them to rear, and getting a pair of Monitor Audio Bronze 2 for fronts. I've read those run quite bright. Would that combination be awkward? The Bose are darn old but in great shape, and I like the looks of them too. The MAB2 are at the top of my budget but should sound much nicer as fronts.