I use CheckPoint...
The makers of ZoneAlarm have gateways for various needs, business and SOHO.
I recommend the ZoneAlarm Z100 for SOHOs and the Safe@Office 500W for SMBs. They can more likely afford the IPS services. Sofaware develops the firmware for some of these.
For do-it-yourselfers, I point to Tom's Hardware, where you can find devices that do well with FOSS/OSS solutions, like DD-WRT.
I've tried DLinks, but it was unsatisfactory, and I turned it off. Their regular firewall appliances aren't bad. I'm too prejudiced to use Cisco/LinkSys, but many gear heads like them better than anything!