Let me start with this systematicaly, so 1 by 1.
1 "If you want to rank high for a keyword, is it not true that some of the best links would be those from the top spots in the serps when that keyword is searched?"
Yes, they would be great links, and if you can exchange links with a site like this, do it. But i would only do it with these sites. and the trick is to make sure they are not using a nofollow tag also, or they are worthless. Yahoo just implimented the "nofollow" at this last update Here is the link
Yahoo! Search Blog: Yahoo! Search Support for X-Robots-Tag Directive to Simplify Webmaster's Control and Weather Update
2."I have read that if you don't properly manage outgoing links with no follow then the outgoing links will drain link juice. Any validity to this? "
Yes, PR, or page rank as it is called is a "juice" bleed system that works similar to electricity. the "juice" like electricity will follow links like elec. follows cords or lines. and this gives what SEO's call PR bleed. you can bleed your juice to other sites. I personaly only do recips to internals from internals for traffic purposes only, and they have to be from a similar pr page. and there is a reason for it. if you have a pr 4 page and recip with a pr2 page, i will lose more "juice" than the pr 2 page, so the other guy gets more from the exchange. this post will explain in more detail
Seo for Link Building and Web Traffic. You can have your cake and eat it to.
I would not just start a link page for exchanges. Building links should be done through social bookmarking, press releases and the primary building system should be articles.. Directory submissions are also a plus for sites needing lots of links.
Read about my linkbuilding system on this post .
little help in getting links
Edwin also posted a great help right after the post for free.
Hope this helps.