I really like all of the 109s from the C series onwards, favourites would have to be 'F' series, 'G' series and 'K' series (oh and the 'T' series)
AIUI there were significant problems with the 309 and the RLM decided to focus on the FW190 D series and the Ta-152 which already were superior in performance to anything promised by the 309. I may be wrong however
The 309 was originally designed to be the definitive successor to the 109. Innovative features included a pressurized cockpit, tricycle landing gear, and a retractable radiator. However, the 309 could be out turned by the Bf 109G and was judged inferior to the Fw 190D and never reached production. The Me 609 was to be a twinned version similiar to the P-82.
The better varient is still hard to say. What are your more looking for: performance or handling. True the K model was the fastest but I believe the G model was by far the better of the latter models. However the E model seemed to handel the best and had better flight characteristics, atleast from what I have read. Whichever model you believe, I think the Me-109 was a remarkable aircraft.
I have to agree with you and I think it was the best looking one of the 2 also. It was sleek and just looked like it wanted fly through the clouds like and eagle. Some of the paint schemes they put on 109G's were just awesome looking. It was a great aircraft.