[Asterisk-Users] what hardware should I use for asterisk? [please help]

[extreme2000 at o2.pl]

Hi,
First of all, I would like to say hello to everybody, it's my first post on the list.

I'm building a pbx for a client and I need help/suggestions on what hardware and os to choose. I've read all I could find on the net, but still can't decide myself. Appart from signal switching, the main concern here is reliability.
The config will stand as follows: 15 sip phone terminals, 4 POTS France telecom lines, 1 ISDN line, 4 ip-providers lines, all this will run on on a france telecom (argh) dsl line (20M/1M)

In the begining there will be quite a lot of load on this network, but in the future the client wishes to connect 30 WAN sip terminals to the asterisk server and add 8-10 ip-pstn lines. From what I've heard Asterisk is quite hungry on ressources, what kind of hardware can you suggest me to use? Is it worth to buy a server mainboard?

And then will the T410P with 4 FXO work together with a T1 (I've heard it was not recommended to use 2 digiums on the same M-board).

The second point is about OS, I thought about some free BSD or Solaris and also Debian, the first two for quality and Debian because it's well documented and I like it, but I don't have any serious opinion on that neither.

Thanks,

Jays