You may already own a DVD burner, but if you're going to buy an internal drive, be smart and buy a DVD burner. The BenQ drive mentioned above will not break the bank, and does just about any type of writing you'll need to do, Dual layer DVD, Single Layer DVD, CD, the mini stuff, whatever, in just about any format. (Disc-at-once RAW, Track At Once)
For example, at work, I purchased a Sony CD-RW/DVD-ROM combo drive, and it cost $35.00. A DVD-R/+R, CD-Burner combo drive by Sony that did so much more cost $39.99. (This was a while back) The point? SPEND THE EXTRA FIVE BUCKS! It's worth it when you'll have the drive that'll do 16X DVD-R, or whatever it supports. It's just absolutely silly to NOT buy a DVD-Burner with them at such low low prices.
If you're into "making backup images" and such, dont go blindwrite. Go with something which will give you more control over what you can do such as Alcohol 120%. And it DOES matter which hardware you choose. As I stated above, pick your drive, and pick your imaging software of choice, then look for a compatibility list that is put out by that software developer. Make sure the drive is on the list. They usually will have a list of drives that will write in certain modes. For example, some really cheap, off-brand drives may not be able to write DAO/RAW, which is required in order to "dupe" a disc properly.
As for chipsets in the devices, it's not REALLY that important, but according to the review I read, the BenQ drive mentioned above had very low error rates, and recorded to most media brands quite reliably. I've had an old Ricoh drive that was so picky it would not write on anything but Verbatim media. I still use Verbatim to this day, actually, but yeah, that BenQ drive is probably the best bang for your buck at the moment. I believe it also includes Nero, which maybe at this time will have been upgraded to Nero 7, but do not count on it unless you can look at what's in the package. (Newegg)
Also, the software bundle is also a determing factor for whenever I want to purchase a drive. I avoid any kind of drive that includes Roxio's Super Coaster Creator, unless you own a version of Nero or something that DID NOT come bundled with a drive. If you think you can fire up Nero that came in a bundle with your old drive and use it with your new drive, you'll be in for a dissapointing suprise. It will refuse to launch unless you have the old drive in the system. Since yours is external, you probably wont run into that problem. This I DO know for a fact when replacing dead DVD Burner drives at work. Sonic is a brand of burning software that's based on the good-old fashioned french Prassi engine, or now known as PX engine, as Prassi was bought out by Veritas a long time ago. Sonic though does a decent job, gives you more control (IMO, not as much as Nero does) over what you can do and how you want your discs burned. I like nero for it's non-skinned interface as well, it's an actual window, things are easy to find, and it's simple to configure. Easy CD Creator has this i-Mac look to it, all fancily skinned up and such, and has been crap since Adaptec sold it off to Roxio (or split, or whatever).
I guess I'm extremely picky when it comes to picking out optical storage units... lol.