Well you can get internal SATA BluRay readers for £130 (probably about $200). Of course you won't be able to play movies on them until Leopard comes along.
As for HDCP (DRM) issues, well PowerDVD works just fine on the PC over an analogue connection (VGA/component), but won't work over DVI/HDMI unless your graphics card supports HDCP. Although I am not sure if this DVI/HDMI restriction is required or just put in there by PowerDVD to keep movie studios happy.
On the PC, all ATI HD series cards support HDCP and most Nvidia 8600GTs also do. But I don't know if Apple has included this feature in current MacBook Pros/iMacs with those GPUs.