As a collector of movies, as well as an avid movie viewer, an HTPC with a blu-ray drive makes sense to me.
I won't fool myself into saying that "I don't notice a difference..."
I do.
Even from 480p progressive DVD to 720p Blu-Ray there is a noticeable upgrade in appearance, particularly for newer movies, for older movies I've seen it's generally a waste of time as the reference material can only get you so far.
The audio upgrade for TrueHD is also substantial.
I definitely don't have one for my gaming and work PC because it's completely unnecessary.
As many have said there are much better ways of moving large amounts of data, and there's little point in making a Blu-Ray game because with the slow transfer rates who wants to deal with load times, that's what I have a PC for.
The BIGGEST problem I have with Blu-Ray drives for computers is the horrendous support of both the firmware providers and the software providers.
WINDVD or PowerDVD support is sketchy, to say the least.
Since Blu-Ray has gone through a few different revisions, presumably fixable by firmware, or software upgrades there are several Blu-Rays that dont work in WINDVD, for example, which is arguably the better of the two.
When it works, it's wonderful, when it doesn't it's infuriating and there's no real help available. It may be expensive to buy a separate BR dedicated player, but it's worth it for the aggravation if all you want to do is watch them.
WINDVD gives you a useless support run-around, and good luck getting firmware support beyond the latest FW from a Blu-Ray vendor. And, believe me one vendor will blame the other when they can.
In short, its hasn't been worth it for me, with the exception of being able to RIP Blu-Rays that has mitigated some of the compatibility issues.
If I had to do it all over again, I wouldn't have bothered buying the drive knowing then what I do now.
It's much easier to deal with a singular vendor of a dedicated player, ideally of one that's already network aware.
I have no problem paying a premium for the privilege of watching something better, that's why I have surround sound and a 50" screen. I know it costs money but damnit I love movies.
What I DO have a problem with, is when it simply doesn't work.