Here are a few of my absolute favorite cards!
The cards below are of the famous John McGraw - a player who's abilities as a coach earned him a trip to the Hall of Fame. I believe he's one of the players that could have gone to the Hall as either a coach or a player; now that's pretty damn pimp! And I loved his nickname - Little Napoleon.
The cards below are both T206's, but with exceptionally rare backs. I found them at auction and bid on them without realizing just how difficult the backs were - more specially, the Tolstoi backs are difficult to find on McGraw, but the Cycle 460 backs are exceptionally rare. You can find Cycle 350 backs more commonly, but any Cycle 460 backs do not come up at all - in fact last year, just on Ebay, I recall seeing only 2 or 3 T206's for auction with the Cycle 460 backs - they are just THAT rare.
These next set of cards are some of my personal favorite - they are the T213's - aptly named because they are "coupon" cards - cards you could redeem for cigarettes. These cards were released only in Louisiana, so there's a level of rarity due to it being a regional release. Although these aren't super rare - they CAN be found, they do carrier a bit more of a premium. By the way, see the grades? Some people believe that due to the weather and climate in the south, many examples of these cards are usually found in the lower grade - finding high grade versions are rare - I've seen a few in high grade, but with these cards, they seem to be either very low grade, or very high grade - I don't see any very often that are middle of the road.