If money is no object, get a SIG 220 in .45 ACP or a SIG 226 in .40 S&W. The former gives you the proven stopping power of .45, but a single-stack 8-round magazine; the latter gives you a compromise between a 12-round magazine and a solid caliber. The 226, as a bonus, can be re-barrelled in .357 SIG, if that caliber appeals to you (and, anyway, flexibility is always a good thing). SIGs are built purely for business. They are extremely accurate, have excellent triggers (the new DAK is surprisingly good), and never jam. One notable feature (may be good or bad, depending on your preferences) is that they are DA/SA with a decocker; if you want to carry cocked and locked, your out of luck.
If you want the single most reliable handgun you can get, seek out a Glock. The G22 is a full-size .40 S&W, the G21 is a full-size .45 ACP. Either way, Glocks have an enviable reputation for taking whatever abuse you can dish on them and keep firing. The only downside for the Glocks is that the factory trigger takes some getting used to.
If you want a Glock but find various features of them annoying, look for a Springfield XD, which comes in the same range of sizes and calibers but is an arguably superior gun, at least in terms of ergonomics and triggers.
If you want a cocked-and-locked gun, the 1911 and its various progeny are the pistols to beat; the Springfield models are generally well-recieved, as are Para-Ordnance hi-capacity models. Kimbers are extremely nice guns (most of the time, anyway). And then there's Les Baer, Wilson Combat, and the other custom-shop guns, but the prices spiral upwards from there.