So, if the dragonborn are real, instead of just a catchy rumor, I'm perfectly okay with them.
As others have said, reptilian people are an old stand-by of both sword and sorcery novels and of D&D (see yuan-ti and lizardfolk). Having a detailed, scaly race in the PHB (for use either as PCs or NPCs) is a pretty good idea, I think; it's getting further from the "all Tolkien, all the time" racial line-up of the earlier (A)D&D editions, but that's not a bad thing.
Linking them with dragons seems also like a good idea; the game is called Dungeons & Dragons, after all, and dragons are the iconic monsters, both in D&D and in reality. A lot of people like dragons, and would undoubtedly find a dragonborn race interesting. (I think this is another case of WotC re-using or re-imagining a name used earlier; I really don't think the DB are going to be templated creatures in 4e.)
I also hope this will ease the worries of those people who were concerned about the supposed focus on fiends w. tiefling, warlock etc.; if dragonborn are in the PHB, you are going to see a lot of emphasis on dragons as well. (And the eladrin are probably going to be the fey/celestial race.)
Finally, what is it with people complaining about names? With eladrin, there were complaints it didn't mean anything; with dragonborn, it's a "lame compound word". Would you be any happier if they'd been named "draccaryn" or something similar? I doubt so.