It depends how much you're willing to spend. For the best deals, eBay is the obvious choice, but not so reliable.
If cost is not really a problem or concern, then you can't go wrong with a Gibson, but they will set you back A LOT. You could also go for a PRS, as they are beautiful to the eye and to the ears, but again, very expensive.
Next step down pricewise would be an ESP or higher end Ibanez. I would recommend either and Ibanez JEM or RG prestige (I love the RG3620Z) or an ESP MH401
Next step, Maybe a decent Fender or Epiphone. I'm a fan of the Epiphone Bullseye Les Paul, or Black Beauty. As for Fenders, i like the mexican roadhouse strat, my dad fixed one for a friend and i played it a few times and loved it.
Another step down and you get into the hundreds of smaller brands like Vintage. I've got a Vintage VP6 and have had no problems with it at all and i love it. The pick-ups could be better though.
There's not really much point going much lower down, as they would probably only last you half a year.
I got my Whitestar off of ebay for £70 and was very impressed. It was just like my brother's Epiphone Custom Black Beauty, but with a slightly higher action, which i don't like as much, but its great.
This summer, i'm going to see if I can build my own guitar. I can get all the materials and electronics of eBay, and i can get a nice set of EMGs 81 / SA / 85 for i. Can't wait!