It's really up to you. I usually don't watch movies on my computer, so having a blu-ray drive would be a bit of a waste. But if you think you'd watch them, go for it.
As for games...well how many games do you see on multiple DVDs? That's going to be the real factor, seeing as (as far as I know) most games are still on single disks. Once it becomes cheaper to put games on one blu-ray disk over a couple DVDs, then I could see them making the conversion.
As for GPUs and monitors, well it depends if you want full playback. of course if you have a monitor that can fix 1280x720 or 1920x1080 on the screen, then you're fine. MOst GPUs have hardware MPEG2 depcompression and most current computers can manage MPEG4 without much of a problem (some cards might have hardware MPEG4 decompression...)