Antec, Corsair, Seasonic, PC Power & Cooling, and Enermax are among the best units. Personally I prefer Antec. Read competent, technical reviews of PSUs (i.e. the ones that include load testing, waveform analysis, etc) at sites like www.jonnyguru.com, www.hardocp.com, www.hardwaresecrets.com, and www.xbitlabs.com.
When it comes time for sizing, there's a good caculator at http://www.extreme.outervision.com/psucalculatorlite.jsp