realmaverick,
1) don't get discouraged - it's complex and obfuscated, but not impossible - I am willing to help you (see below), till then remember...
2) the PR you see in the toolbar is often wrong or out of date - don't rely on it or care about it - it is just one metric to use out of 20!
3) crappy sites will inevitably get removed from the index. What you think is crappy and Google moderators do is two different things. You could always make an official spam complaint against them if they are spammy
4) senuke links are of low value, possibly even weighing AGAINST you - you have to be very careful and do senuke links the way NO ONE else does, or they a will have no to negative value - remember EVERYONE uses those same sites that senuke does regardless if they are using senuke per se
5) also, it may take months for those links to give you any good (or bad) link juice - it just takes time to spider them and for that data to proliferate to the other data centers - did you ping or index those links in senuke?
6) at high PRs it takes thousands of links to make any signiificant opsitive difference, but much less links to make a negative one (in theory) if you are already close to he "bad backlink percentage" threshold.
7) IMO with such a valuable site, IF YOU DO NOT KNOW EXACTLY WHAT YOU ARE DOING WITH ADDING QUESTIONABLE BACKLINKS, then DON'T. It's not worth the risk on such a high value site getting banned or penalized. If you are getting good links from viral content, then keep doing that. There is no way you can EVER get penalized from having too many people like you.
8) There are WAY more metrics that could be holding you down / propping them up. What's your bounce rate? Avg. time on page? Do you have dup content, thin content on page or across pages? Too mnay ads above 700px, etc.?
9) older sites are often grandfathered into their state, be that either penalty or "useful" or even "vital" - google is often slow to change on older sites (for better or for worse) - that's the main algo I am describing, panda happens ALL TOO QUICKLY :-) Panda is not (yet) part of the main algo
[edited by: tedster at 9:10 pm (utc) on Oct 21, 2011]