I'm not in a hurry to get one myself, the only thing that tempts me right now is Superman Returns on HD-DVD.
That said, as I already own a 360 the HD-DVD drive seems cheap as chips. It's £129 and includes the remote and a HD-DVD copy of King Kong. For that price, if I did decide to get a HD-DVD player I'd be highly inclined to pick up this one. Even if it turns out to be not so good, it's still so cheap.
The big difference between the HD-DVD addon and the PS3's internal Blu Ray drive for me is the usage of each. The HD-DVD addon will be bought by largely AV enthusiasts who want to watch HD-DVD movies. Over at AV Forums, HD-DVD is showing to be clearly the preferred format.
The PS3 on the other hand will have a Blu Ray drive which I believe will be mainly used for games.
Movie sales will go a long way to determine the next gen format war and HD-DVD is leading the way in terms of disc sales.
However, I'm personally happy with upscaled DVD's so I wouldn't mind if neither formats took off.