Personally, the number of links in your blogroll depends on your niche and your visitors. At some point, your blogroll (if it's in the sidebar) may become so large that it's more of a distraction than useful tool to your visitors.
On a number of my blogs, I've taken it a step further and given my blogroll a separate page instead of having all the links appear in the sidebar, while on other blogs (my personal one comes to mind) I leave it in the sidebar.
As for link strategy, it's good to keep things balanced naturally. I'll say it again,
the key is balance. Don't be stingy with the
linky love because you're afraid of sharing the wealth -- it's actually the opposite. I've had pages get
higher search engine placement in Google when I added a few
quality outbound links.
Be mindful of who you add to your blogroll, make sure they have a site that not only search engines will love, but also your visitors. Provide appropriate links to other sites in your blog post, and try to avoid linking out to bad neighborhoods.
And make sure to seek out quality inbound links from directories as well as other blogs/websites.
My opinion only, and your mileage may vary.
~ Teli
And Sarah, I completely agree about Akismet - less than 2 months installed and it already trapped over 10,000 spam comment at my personal blog.