I have almost the same setup as you, except for the mail system: I am just using either GMail or iCloud server for that. TimeMachine and CrashPlan work really well and do their job totally in background without any visible impact on my work. I really like CrashPlan and went initially for a 3 years unlimited plan: you can get a really good deal usually around black Friday where they drop their yearly unlimited prices.

All my macs are now setup with CrashPlan.