Hammered sixpence of Elizabeth I ... or is it Morgan dollars? Yeah, gotta be the Morgans. (although Liz I's 6ds are pretty cool)
I sure expected a lot of Morgans. They are a pretty nice coin to collect, mostly because they are readily available in Mint State most of the time.
Early wheats, (High grade toned brown examples) are my favorite, but if it appeals to me in a unique way like error or unusually strong strike, or intersting color... plus a decent price, then it is my favorite.
I'm partial to wheat pennies and the Capped Bust designs, particularly the quarters. They're just so much fun to blow money on....
Walking libs, franklins, pre 33 gold of any denomination, and since i recently purchased some large cents, those will become a favorite! I am not a big red fan, i like the hershey's dark brown cents. I actually enjoyed my first 2 so much, I have invested in Bob Grellmans large cent variety book. Should be an awesome addition to my library of coin books aswell!
British large pennies, first half of 20th century. Got a few keys in there, but overall very affordable, pretty, etc. I also like switzerland's 5, 10, and 20 rappens, that have been going on for over a century with no changes other than metal
Mexico has many great collectibles which I like. My number two would have to be the Eastern European nations and number three the French territories. Walking Liberty halves are my favorite US coins, as well as full step Jefferson nickels.
My favorites coin series are Seated Dollars, Leopold Thalers, Classic Commemorative halves, Standing Liberty Quarters. But sorry, I collect exonumia.