This is one of my favorite shows. The kiss was great, especially because they were both caught off-guard by their reactions to it. Remember the episode where Amy got had a reaction to just touching Zach (one of Penny's exes) and then no reaction to holding hands with Sheldon? This current episode is definitely may be the start of something interesting.
As to Penny, it will be interesting if Kaley (Penny) does get pregnant now that she is really married. I also want to see what will happen with Raj and the vet.