4. Storage is cheap
No matter what a salesman tells you, storage is cheap. You don't need Fibre Channel, and you probably don't even need iSCSI. Most SMB-aimed storage devices like the Synology DS509+ pack more than enough features, reliability, capacity, and horsepower into a small, cheap box than you'll use for a while. You shouldn't throw all your eggs in the cheapest basket, but you don't need a $25,000 storage unit, either.
5. Buy the best reasonable backup solution you can
No, you don't need the dual-drive robot, but you do need a solid, high-capacity tape drive and a bunch of tapes. SMBs tend to live or die based on the availability of data, and if you're operating with a small or non-existent IT department, these tapes can be the only thing between a functioning company and oblivion. I'd advocate disk-to-disk backups here, except that SMBs should be taking tapes to an offsite location (home) weekly, or even daily. If you're particularly diligent, buy a few 1TB external USB drives and run monthly backups to those, too.
6. Two servers: That's all
Naturally, this can vary with the size of the company, but if you work with fewer than 100 people and are using a modern hypervisor, two dual-CPU quad-core servers with enough RAM and storage will be all that's required to run your whole server infrastructure. If you add a physical server to handle backups, it can be an entry-level box that can run the tape drive.
7. You probably don't need Cisco
You do need network switches and firewalls, but you don't have to buy Cisco. I've been running Dell PowerConnect switches in production for four straight years in some networks without a problem. They cost roughly 25 percent of the equivalent Cisco product, and they do what they need to do. As for firewalls, stay away from consumer-grade devices, but again, you don't need anything terribly expensive. You can get a decent SMB-class firewall with VPN tunnel termination for a few hundred dollars these days.
8. Desktops are cheap
A basic business desktop system with maybe a Core 2 Duo processor and 1GB or 2GB of RAM is probably more than sufficient for most users. Dell sells a Vostro system for $419 with 2GB of RAM and an 18.5-inch LCD panel. Barring hardware problems, that level of system is likely to last you many years in the future.
9. Operating systems aren't
Careful when buying that Vostro, though. By default, it comes with Vista Home Edition. You'll need the Business Edition, which adds 25 percent to the price -- bringing it to $518 for that whole system. Unfortunately, there's no much you can do about this, except...