I would start off with a nice Dell PowerEdge Server. They are tailored to small business and if your HDDs ever drop you simply slidde a new "blade" in and It will automatically configure the new HDD inside the blade with your RAID setting.
Look into Microsoft Small Business Server 2003 .... for about $600 you get Exchange Server, Backup Utilities, Remote Applications, Outlook web access, etc. This version of Exchange server (If i remember correctly) is not the expensive Enterprise Edition, rather its limited to 75 employees.
As far as a firewall goes, most DSL modems (like the Cisco 675/678) come with NAT and firewall abilities and would be the equivilent to like a $75 SoHo Watchdog and they usually come WITH your DSL subscription (if you buy business DSL).
Get yourself a big enough Switch to handle your users.... if you have less than 50 employees usually the $150 24 porters at Comp USA will do you fine with the amount of backplane bandwidth.
As far as backups go, run your Backup Wizard in your system tools on each computer and schedule the backups to run at a time every nite when the employees go home. Next get your self a 120gb External ethernet hard drive and plug it into your network. Share it for all users/create subfolders with employees names. Then in your backup wizard specify that as the location that you want to save your employees backups. You can also store it back to your dell poweredge just as easily. Also, to decrease backup times at workstations; at the server create a new folder for each user, go to each workstation and right click "My Documents/properties" and respecify the target back to the new folder you just created back on the server... this way "my documents" acutally lives back on your server and your server backups will take care of all that... plus as an admin you can browse and snoop through all your employees "my documents" folder back at the server without creating a share on your workstation.
Antivirus: Norton Corporate= nuff said.
Heres my suggestion for not spending a fortune on licensing for MS Office on every desktop. Instead get licensing for Outlook 2003 only. Then go to Openoffice.org and use that. This is an "open architecture" office suite that parallels MS Office and is 100% compatibale with all MS Word .docs and MS Excel .xls. and MS Powerpoint .ppt's. You will see no difference (except a few minor cosmetic differences). But yes OpenOffice.org's suite includes the equivilent to MS Word/Excel/Powerpoint. The Best part is that its FREE! YES I SAID FREE! And your employees will never know the difference from a functional standpoint. *I suggest using Outlook 2003 simply because if you are running Exchange Server on your Dell Poweredge you wont run into any problems with MS tech support if you are using Exchange/Outlook combo
Otherwise, you can use the free Outlook equivilent that comes in OpenOffice.org.
Backups Again: You have 2 types of backups.... 1: Server Backup 2: Workstation backups.
*Lets talk about Server Backups. If youre running MS Small Biz Server 2003 it will have a backup utility that you will configure what you want backed up and you will configure its scheduling to back up whenever you want. You will configure that Utility to back up to your hardware unit (being your tape drive). When you buy a Dell Poweredge you can get it shipped with a tape backup (which I reccommend) any server you buy make sure it ships with ALL THE HARDWARE YOU WANT -or you could get into warranty situations if you decide to add your own (Internal).
*Workstation Backups: These will typically be system configurations and docs that are on the local computer. Like I mentioned earlier... users tend to save stuff to "My Documents" so if you redirect the target of My Documents back to your server... all their info in My Docs gets backed up with your scheduled Server Backup. So with docs taken care of you have programs/system info to backup. Like I said, set up a shared external ethernet HDD somewhere on the network and create a bunch of subfolders with their names on the folder. Configure their Backup Wizard (at the workstation) to back up "everything on my computer" to their folder on the external ethernet HDD and schedule the backups to run in the evenings after they have gone home (or lunch time if you have a scheduled lunchtime). Then if you ever need to restore from backup you can simply pull that backup restore file down from the ethernet hdd.
*Note: Instead of using an external ethernet HDD, you can direct to store your backups on your server but if youre doing the backups during working hours, it will really nuke your server CPU/Memory and bog stuff down.
.... email me if you need any more help.. ill be happy...
oh and if you hear of any job openings anywhere in CALI, im lookin ;-)