IPS/IDS for heavy content site


My site would have heavy content (video/pictures). I'm looking for an efficient IPS/IDS solution which would not introduce much of latency. I'm more familiar with Cisco ASA and also familiar with Juniper, Foundry and others. I also came across snort but haven't used it before. I'm more of looking for an appliance (for the ease of configuration,support etc...)
Could any one share their thoughts on performane of IPS/IDS from this vendors?
Janakan Rajendran