since I never had any suicidal ideas - I never did any link exchange or link farming. looking at G's tendency to clean up all attempts to artificially inflate popularity of a site ....
many of the linkfarmers got penalized in recent 12 or so months and lost serps as a result. just look at OLD posts here in DP forum.
I am generally do link exchange with relevant sites and relevant categories of directories. I am also using link manager some times.
Y site explorer shows for me some 46,410 BL 99+% of them are generic link from happy readers. a few hundred are BLs from RSS/blog directory submissions, RSS feed SSI by other sites and a few NON-recip direcotry submissions. hence age is the key thousands of unique self created content pages over many years leading to many happy surfers and forums linking one way links to me.
I believe that the best way to get link without much effort is to build quality content. You don't need to ask people around to link to your site. They will do the favor to link out to you.
Don't do link exchange. But if you do then do it with websites in Google that are on the first page of your target keyword.
I receive email requests for link exchanges regularly and I just delete them. That's because after a while, it's really hard to keep up with the link exchanges. I still prefer article submission (not just because I offer such services), but because 1) It's free if you have the time to submit articles yourself 2) it's really long term and viral if you have good quality articles 3) the results are measurable and predictable, compared to link exchanges. Just my 2 cents :0)