I have a lot of guitars and I use them all often. I'm primarily a blues player, so most of the time I reach for my strat (it's a early 90s 62 reissue made in Japan). The strat is really good of doing funky rhythm stuff. When A song calls for a more distorted sound, I grab my (Epiphone) Les Paul. When I'm doing something with a lot of dive bomb tremolo stuff with even more distortion I use an 84 Kramer Brietta. I have an Epiphone Dot (simi hollow body) for doing mellow jazzy songs or BB King sounds. When I want a tone that sounds spicy and has a bite I get out my Jay Turser Telecaster (I just bought this one, for $150.00 you just can't beat it) and last, for playing slide, I use a Gibson Les Paul Jr Special (this guitar has the old style P90 pickups). I also have a 64 Gibson Firebird, but I don't like to take it to gigs because I'm afraid it'll be stolen.
None of these are hard rules. I just grab the guitar that I think will work, but if it doesn't, I'll put it down and grab something that will. I play all of these guitars through a 50 watt 64 Fender Bassman 2X12 and I play effect free for the most part. For recording, I use a Johnson J-Station most of the time.