Try Speco DVRs or KALATEL (Score 1, Informative)

Speco DVRs (www.specotech.com) are very reliable.... i've been installing cctv systems including DVR's for 6 years. From my experience you should try non-PC based DVRs..they're more secure, reliable and dont crash at all.. you dont need a firewall to protect the dvr from viruses and they work with dynamic IPs too... .... Speco has a great line of DVRs that are based on an embedded linux kernel....they're cheaper than Kalatel (GE) dvrs....