ISA can be a bit of a nightmare if u have a hardware firewall you will be fine - all ur clients will have the xp firewall on them anyway.
SBS 2003 will be fine for you and comes with lots of nice wizards to help but u sound like ur not to confident about setting up a 25 user network and getting it all to work - lots of stuff can and does go wrong
i currently support 8 SBS sites and it keeps me busy luckily its mostly users being silly than anything wrong with teh software.
and as said dont host a website on ur connection hosting a webserver is
a: security risk if all ur apps / data is on one machine (sbs2003) well it can be ok nothing is ever safe on the web
![Smilie](images/smilies/smile.gif)
b: a waste of bandwidth - get a hosting package for 2 pound a month to do a better job than ur line will.
dont be fooled by server specs for a sbs server it will run on anything really u just need RAM as exchange will eat it up.
go for 2GB min ram
u want to consider storage - sata or scsi if you can afford it - dont worry about sata horror stories, hard drives break all the time ive gone through 6 scsi drives at the sites i look after and no sata drives have broken yet - oh and raid 5 them
u want 2 network cards (north internet / south lan)
and go for a dual core 2 cpu rig maybe from dell but dont configure it online - phone them get an email address then haggle with the indian chap over what u want.
consider backup as well - onsite backup as well as an online backup and rotate the backup media onsite.
good luck