I recently got a Castle textile mesh jacket, which I switched to from a full leather jacket. I had intended to wear the leather whenever it wasn't hot, but so far, in spite of some cool days, I haven't gotten the leather out again.
It's lighter than leather, keeps me cool, has a windproof/waterproof liner to put in when it is cold and or raining, and the material is somewhat water shedding, I've warn it without the liner through a few rain showers and it kept the parts of me that it covers fairly dry.
As far as protection goes, it has armor and the material is supposed to give good abrasion resistance. I know that good leather offers better abrasion resistance (keep in mind there are plenty of crappy leather jackets that are too thin to offer good abrasion resistance, and some are constructed so poorly that the seams will give and then it wont' offer much at all!) but from what I've seen, that level of protection simply isn't necessary for the street. In racing, they run leather because they can slide out in a corner, hop back on the bike and finish the race, where a textile would save your skin from that slide, it would most likely be damaged enough that you should buy another jacket.
If you do want leather, though, I've heard great things about River Road. I know a couple people who have river road gear, and they all seem to love it, and the prices are downright great considering the quality. I've also heard of them really going the extra mile about getting a jacket to fit right, so if I was going to buy a leather jacket, I would probably be looking at something from them.