I wrote an article about this based on my experience with thousands of Webmin/Virtualmin/Usermin users:
We've been running 6.06 TLS with no problems for almost a year and just recently we moved our staging/production to 7.04 and we (as expected) are seeing no difference. We compiled apache and all libs we needed from source and never used apt-get for anything.
Besides, is it really important? IMO production server is just that: a production environment. You set it up just once and you're not supposed to mess around alot.
That's why you should have stuck with LTS. 7.04 will likely be EOL'ed in the next few months (unless they branch another LTS version of it), and then you'll be forced to upgrade under duress. Long life cycle is probably single most important factor in choosing a good server distribution, because "you're not supposed to mess around alot".
I've done very poorly with Ubuntu. I've tried installing it twice. The first time, it installed successfully but then when I rebooted it trashed my RAID configuration and dropped into single-user mode. The second time, which was last week, the installer kept hanging in bizarre places. The whole distribution just seems to be geared toward very simple hardware configurations and chokes at the slightest violation of its expectations.
Also consider a BSD, though.
Otherwise, I also recommend CentOS, especially if your hosting provider lets you run it with SELinux enabled.
It seems to me that Ubuntu is pretty much like Debian with a more shorter upgrade cycle. Is that impression accurate? Also, does Ubuntu have any extra overhead that a Debian system might not have?