I agree with Aschleman. There is a reason that straps are adjustable. I play a strat, and when I have played a friend's LP (with his strap adjusted for him) I find myself holding the weight of the guitar with my left hand.
Start high and lower the guitar as you play to find the "sweet spot."

My advice on a new guitar is don't let the name fool you. If possible, go to a music store that has used guitars. Spend the day and play them all. Most prices start at 1/2 of retail and go down from there. You might find that a Peavey, Schecter, BC Rich, Hamer, Ibanez, or Epiphone has the right feel and fit for you. Don't worry about who makes it. Worry about how it sounds, feels and what you can make it do. I now own a Yamaha Acoustic/Electric that sells for $300 that I paid $99 for, and an epiphone Dot that I paid $129 for.
Buy the best guitar you can for the money you have. (or can borrow)