Mike:
I have a httpd, sshd, and ncftpd. I use iptables with very tight parameters, including a complex libipq filter I wrote. I am attacked all the time, but I don't think much, if anything, gets through.
Tim:
It only takes one to give you nightmares.
Mike:
top: up 374 days
Though what does that prove? Getting compromised doesn't have to change your uptime. You could be owned for any amount of that time, but never know it. I wouldn't tout an uptime, in itself, as an indication of okayness. If anything, an uptime of that length on Linux indicates that you haven't updated a kernel in a long time, which *may* not be a good thing.
You said you didn't think much or anything had got through (i.e. you don't know, for sure), which was my point (that just one breakthrough is a problem).