I'm getting a new laptop and it isn't going to have a DVD drive so I'm going to get an external one. The question is whether I should get a bluray reader or not, a br burner is far too expensive. The idea being that I could use the HDMI out to use my laptop as a bluray player on a tv, or just watch bluray movies on my laptop, which has a FHD screen. Is it worth it? Or should I get a cheap DVD drive and a separate bluray player?
An external DVD R/W drive for the laptop and a stand alone BD player would be my suggestion. While you are watching a movie with your feet up, the laptop can be independently doing virus scanning, or some other time consuming task.
Also, laptops have very poor screens compared to most HDTV's. The Contrast Ratio (true not dynamic) is too low and viewing angles aren't the best.
I would wait until USB BD recorders become inexpensive and better.
Standalone BluRay player:
BluRay has been a bit of a nightmare and it hasn't stopped yet. A new addition will be coming out in a year or two so I wouldn't spend too much on a BluRay player. I'm talking about the fact that films are going to be produced at 48 Frames Per Second rather than 24FPS. It will start very, very slowly though and will take several years to become an issue.
The two movies which prequel The Lord of The Rings entitled "The Hobbitt" are being filmed by Jackson at 48FPS. That means only newer BluRay players (and no DVD) will play this. No current BluRay player (except possibly the PS3 with an update) will work.
I recommend the same thing as the other guy:
1) USB DVD burner
2) inexpensive, but still good quality BluRay standalone player