Re: Stratocasters
For a quality strat guitar that can cover most blues to classic rock well, then a PAF type Humbucker voiced bridge pup is a good strategy. Both the guitrs posted in this thread are like this. I like a HB in the bridge with SC's in the neck and middle, so I don't have keep changing guitars all night long, although with the right boost, and a tone control put on the strat bridge pickup; the stock single coil strat bridge pickups do okay.
The vintage reissue strats make a very solid foundation to work from. They can be had used for decent prices.
The Eric Clapton strat, is also a very good tool for your stated purpose. It has an onboard mid boost that allows it to get both Fender and Gibson type sounds. I was amazed at how well Eric; using these guitars, sounded on the recent cream reunion CD's. If you dislike the noiseless pickups these come with you can always replace them.
Since you asked about amps, (it's okay in this context isn't it?) you can't go wrong with the classic Fender 5F6 type circut. It will cover everything from BB King, to skynard, to ZZ top and more with aplomb. They can be loud enough, but not too loud, and they usually have good dynamic tone. Amps based on this circut are the Tweed 4-10 bassman, Marshall JTM45/bluesbreaker amps and their various derivatives.