Hi Bruno,
Regarding a NAS, I have recently purchased a
Synology DS101g+ with a 200GB drive for about AU$600, and I am very happy with its performance, quietness and ease of setup. They now support 500GB drives.
I only have a 10/100 switch at the moment so I am not getting the benefits of its Gigabit interface, but it gives me a future upgrade path.
I have a 5-in-4 card reader attached to one of the rear USB ports, and it will see at least two of the slots, although I think it will only recognise one card at a time - I haven't tried it with multiple cards at once.
As far as a UPS goes, I have been running a
Sola 625 1000VA, although Sola have now become
Powerware and this model appears to have been superceded.
I have two PC's, one with a 19" CRT, 2 sets of PC speakers, satellite modems and various USB hubs and network switch and occasionally the Empeg all running off it at once, and it is running on generator input in ambient temps of up to 40C, yet it has been rock solid reliable for at least two years, with only now and then a 'cabinet overtemperature' error message. The battery still gives over 20 minutes shutdown time. Highly recommended!
HTH!