actually i think a combo drive is not a 100% choise, on a laptop OK but for the cost of such a drive I would get both a decent cd-burner and a separate dvd-reader...

a dvdburner capable of burning cd-r, cd-rw, dvd-r,dvd-rw, dvd+r dvd+rw and dvdram. costs about 90€
a combo dvd-reader/cdburner costs about 60€.
yes i know, 30€ is not just small change, but it is money well spent in my opinion.
otoh those combos are better than a dvdreader (about 32€).or cdburner only (30€).
but as you can see you get both for about cost of a combo drive,
that would give you more options. like booting knoppix on dvd-reader and using burner... you choose.
kindly OErjan