In 2008 I grew Jalapeño M. Nice flavor and heat, medium size. But, as someone else has already mentioned, the midsummer pods were quite a bit hotter than the spring or fall pods. As you can see in the pik here, the fall pods had very little to no corking, even after they turned red:
In 2009 I grew Biker Billy and Jalapeño Early. The BB's were grown in shade with lots of hardwood mulch, and the Earlys were grown in full sun in a very hot and sandy garden, so it's not fair to compare the results, but I will anyway. The Earlys were very productive and every bit as piquant as the BB's, I would estimate 10,000-20,000 SHU, and had wonderful flavor and aroma. The main difference I saw was that the BB's were larger. (Sorry, no pix of the BB's; they're on another computer at home):
Jalapeño Early:
For 2010 I'm growing Jalapeño Early again, as well as NuMex Jalmundo. I believe because of the extreme heat we've had for the last 3 weeks the Jalmundos are corking and blushing before they reach full size. But the fruit I have tasted so far is excellent, quite juicy and crisp with a nice sweetness behind the typical Jalapeño bite of 5,000-10,000 SHU:
Baby NuMex Jalmundo. This pik is about 3 weeks old, so they are larger than this now, but as you can see, they are chunky pods:
If I was forced to pick a favorite Jalapeño, I would have a hard time, because every one I've grown was my favorite, at the time. I think as long as one uses good soil and the plant gets plenty of light, plus all the other care a good pepper grower needs to give his/her babies, it's hard to grow a bad Jalapeño...