pageoneresults - 11:21 am on Jan 9, 2011 (gmt 0)
I don't pay much attention to WMT's indexed pages reporting. I've found WMT indexing reporting to be not reliable.
Hmmm, I'd pay real close attention to what GWT is reporting. I've yet to find it unreliable and I've used it for years. It has been responsible for early warning alerts for a variety of technical issues.
If Google is showing a large number of pages from your site and you don't have that many, it usually means one thing, you've got multiple paths to the same content and Google have most of them indexed. I see it happen on a regular basis.
Also, the one thing you want to pay special attention to are Crawl Errors, especially the Not Found ones. If your site has an excess of internal 404s, Google will whack you slowly. Then all of sudden, you'll wake up one day and see that most of your pages have been purged from the index. Once that happens to you, the next time GWT shows something out of kilter, you'll take action on it and not ignore it thinking that it is buggy. ;)