Best server configuration?

From an efficiency standpoint, what is your thoughts the best way to arrange your servers? Given six boxes + a DB,

*is it better to set them up in a load balanced traditional 3 tier environment; 3 Express boxes and 3 Example boxes which are communicating across the network?
*Or would it be better to set them up as a load balanced node environment with each of the six boxes containing both example and express?

The latter would reduce chatter and latency across the network but depending on the load balancing configuration, could hose one of the servers.

If you have an environment already set up, which topology do you use? Do you have another topology to recommend?

-Whiskey Tango Foxtrot

Well from what I have seen, I might consider something like 2 express boxes and 4 server boxes in a traditional load balancing setup given 6 boxes total. The majority of the load we see is on the server boxes in regards to memory/cpu usage, generally the footprint for express is quite a bit smaller. We have been running in a configuration similar to this and our express has always been stable (can't say the same for server). Admittedly our user base is relatively small, but it works quite nicely for us.

One thing I would also consider is that from a security standpoint, you are most likely in a better position having express and server on separate machines, which can allow you to put your express frontend outside your firewall for example if you needed, but keep the server within your more secure network.

According to DC they have had better results having Express and Server on the same box using a load balance environment. I believe DC saw a dramatic improvement with this set-up. This is the set-up that we went with and it has been working well.