^^ Great config jas. The Apc 650 va will do so no need for a 1000va ups.
Regarding speakers, the z5500 surely are great and has been a great performer for the last 5 years in digit mag.
But for an enthusiast grade htpc, we should looking for brands which are experts in sound engineering. Brands like BOSE , B&W , DALI , MORDAUNT SHORT, JAMO, KLIPSCH , MONITOR AUDIO , ANTHONY GALLO , ELAC , WHARFEDALE etc...
These brands sure are expensive but are best for those with budgets >> 40k atleast for the speakers only. And lets not forget that these speakers require an AVR ( AUDIO AND VIDEO RECEIVER) from DENON , ONKYO , SONY etc..
I will put up a pricelist of some models of the above mentioned brands and they can be given as an option with the above config for those who can afford them along with an htpc.