“Is 10 too much, or acceptable in your opinions?”
For most anybody ten is way too much. A domain of under 200 pages, with a PR6+ main page, ten could be okay. Any domain bigger or PR5- is cutting its own throat.
“Also, when looking for links do you care if the other page has got a gazillion other links as well?”
You better! Getting a link on a page with a gazillion links on it is close to worthless, unless the page is more than two PR points higher than you, or a really high-quality themed site.
Whatever pagerank a page has, say it is is worth a value of 100 soldiers. You are able to send the value of 85 soldiers to other pages (without hurtingyour 100 value). If a page has 90 links on it, each linked to page is getting less than 1 soldier.
On the other hand, if you have 25 links on your main page, and ten of those go off domain, then you only send 15/25ths of your available 85 soldiers to defend your own domain.
Linking out is very important to define the nature of your domain, but at best it should be a PR wash and likely will lead to a significant loss (because all links to and from your page get diminished by that 85% dampening effect).
(Pages with a gazillion links should be avoided anyway since just by volume there is a good chance they link to bad neighborhood sites.)