My CD-Rom was toast and UT2K4 was coming out on DVD, plus I wanted to be able to watch movies on my 21" monitor when the urge strikes me (or the TV is already taken). Thus, DVD player.
Also I am archiving a large (800+ tapes) VHS collection of my gramma’s. Thus, DVD burner.
Similarly to upgrading to XP, once I had a need I went ahead.