I am just like you, I started with Post war but I aminly centered on HOFer rookie cards. Then I drifted to HOF prewar and I love collecting from a variety of sets. When you sit down and browse through your entire collection it is marvelous seeing all the different colors, backgrounds, backsides, frames, different time periods, and even different HOFers from different times. I love being a subset collector.
Might I also recommend sportscardlink. They are the only ones I used so far, but they were fast as hell, great service, great guys, and they accept credit cards!