server build for work, remote access and exchange

[black_b[ ]x]

i'm out of the loop on server configurations. We need something to handle file sharing and Outlook email for 5-10 people. It'd be nice to import the old PST files for the users so they can still access it, probably around 16-20GB worth of email. They also want to be able to access their email and the network files from outside the office (VPN?). the biggest load will be the email. for file sharing, its just word documents, visio, powerpoint, etc. that are open at once.

is windows 2003 server going to be required for that setup? or is the small business server a better choice? i'm not sure what extra is included with SBS, but we will need newer versions of Office and outlook for almost everyone.

Since we have dual and quad cores available now, is it worth going to a two-socket motherboard? seems like two dual-cores would be more fail-safe than a single quad core.

we will probably do another RAID 1 setup, is scsi a better choice than sata? should we get separate hard drives for holding the exchange/mailboxes? I don't think the server is getting hit that hard, hopefully SATA drives are sufficient.

Also need a backup solution of some kind. Are tapes worth it? they seem really expensive, and nobody even takes the tapes we do have offsite. what other options are there?