Yes... I setup and looked after the monitoring for bluecoat devices from F5's for a few years at a previous position. Basically we had multiple monitors... Firstly an ICMP monitor on the node itself (Which I usually configure as the default). Just to ensure connectivity was there (Because it can timeout quickly compared to an HTTP check). Then you have X number of HTTP checks that run via each of the F5's. We used several sites that were heavily hit by our users. e.g. news.bbc.co.uk, a few of our own websites and several others.
Then set a MINIMUM number of monitors that have to be up... e.g. 1. So if one website goes down, your F5 still gets used...
Oh, I had a thought... You could also set these monitors to be inline maybe... Although I haven't tried, YMMV...
H