Planet13 - 6:21 pm on May 30, 2011 (gmt 0)
No matter where you get the links from, having a good mix of anchor text APPEARS to be very important if you wish to avoid a Minus 50 penalty (often called an Over Optimization Penalty).
It would be good to take a close look at the back links of the top ten competitors in your niche and see what types of links they have, and whether they have benefited from the types of links which you hope to obtain.
It might be a good idea to take a look at the competitors in the 50 to 60 range and see if there is a consistent patter of spammy back links.
I believe (no scientific data) that google will be more likely to IGNORE spammy back links in certain niches and PUNISH spammy backlinks in other niches, depending on how competitive they are and how many searches the keywords get in a given month.
This is based on looking at the posts in this and other forums from people claiming to have received a minus 50 penalty.