How to select a novel to compare yours to in the query

First, thanks for all the great comments in the other thread-Future for historicals.

I've heard agents like the submitting author to list a recent, published book, and preferably a debut, as a comparison in the query letter. My problem is that while I read a lot of books-I can't read all of them (sigh). Plus, I read outside of historicals. I'm sure there are a lot of excellent books that don't become best sellers, and are smashed in the lower level bookshelves at B&N (a seriously bad place for an author to end up IMHO, but better than not being published). I'm just not sure of the boundaries...reminds me of dark water.

What procedure would you follow to locate such a comparison for your novel, if you needed too? The quickest way you would use to find similiar books.

Agents often remark that in queries the author should stay away from certain big name authors as it would be rare for an unpublished author to measure up. (This is sometimes noted as a turn off)

Bottom line, I wonder how important is this type comparison in the query?
Did you use it? Thanks

Puma,

I posted here to guage the feelings of historical writers first, because I'm tweaking my Q that just has never felt quite right to me. Since I'm debating using a comparison, I hoped some here could point me in the right direction from their experience. I've checked out the Q's in SYW and commented on a few. I wanted to be an active thread participant before throwing my own work in for critique, which I plan to do in a few days.

Please move the thread if it doesn't belong here. Thanks.

Wow. Thanks everyone.