We'll do the same thing for apache. There will be a wiki page just like the PHP and Mysql ones with any extra steps (there are some deprecated modules for example) you'll have to do.
The deprecated modules should normally give a clear error when restarting Apache
Are there any other important things? Anything about Plesk? According to http://kb.parallels.com/762
, it should recognise the upgrade automatically.
What are the features for which we would want to have 2.2.17? I like to use vendor supplied packages as much as possible, since I feel they are more thoroughly tested and I like that they aren't moving so fast. For PHP I see the use of upgrading (clients asking for more recent versions because they want to use features only available in later versions), but I'd even rather stick with the vendor supplied MySQL packages for instance. I haven't felt the need to try Apache 2.2.17 from atomic-testing yet.
If upgrading Apache is optional, I'm not against putting it into atomic, but I probably will stick with the vendor packages. If other packages are going to depend on the newer Apache, well, I'll just have to play along.
MySQL 5.1 and 5.5 are adding a lot of features too. Though small users won't use them yet. And there are also a lot of performance improvements, as there's the competition of Drizzle, MariaDB and Percona.
Apache is getting competition from Litespeed, lighttpd and nginx which are faster, more lightweight solutions. And the first beta of Apache 2.3 was released a couple of days ago.