I can only tell you about the HD. since it is a sata disc speed-wise is no different internal or external. internal you will have more heat problems but no added cables and devices to sort on your rack, and external will be the opposite. - cheers
In regard to hdd, I have internal, and find it great. As for HD cable boxes, have read of a few people who've got the cable version, so guess it's available np
I use 500GB esata hdd, and I find it generally OK except the following:
1. Browsing HD movies is very slow.
2. When forwarding MKV movie the DM crash.
3. No forwarding when viewing MPEG movies.
I understand that 2 & 3 above may not relates to the use of esata. However I thought I share my findings with you.