if you do go for a burner and you have costs in mind, remember that you'll want something that burns Verbatim dual layer media that is 2,4x rated, at 4x at least. I chose a benQ 1650 and couldnt get it to burn at 4x without speed patching it, and once i;d done that, (maybe because my comp is old), it would spit out coasters. So now I just use my drx-800ul for DL burns and the 1650 for burning a SL dvd.
As others are saying, read the reviews and see what suits you best. If you want a good burner, i.e good burns, fast times, then the 1650 is good if you can afford the 8x media. Otherwise, see if you can find a burner that gives as good results burning at 4x as it does at 2,4x with MKM 001 DL discs.
*2.4x = about 45 mins
*4x = about 25 mins