That's like asking what's the best pizza under $5.00
If you're TRULY only want to buy once, buy something just $300-$500 more than you're current budget.
Now that being said, there really isn't a "best" some are better than others, but "best" is entirely subjective.
For around $1K (you'll have to do some shopping around), I'd take a look at a stainless steel Springfield Loaded, Kimber Custom II TLE, and Colt XSE line.
If you can go up to around $1500, start looking for Springfield TRPs, Dan Wesson Valors, some offerings from Les Baer and your nicer Kimbers. I generally don't recommend Kimber, but it's your money buy what you want.
If you want to be a couple hundred under $1k, get a Ruger SR1911.