If I may through my 2 cents in...I have an e-commerce site with various products on a variety of pages. At first, when I decided I didn't want to carry a particular group of items anymore, I just made a new page and deleted the old. The old had a
PR of 4 and the new had a
PR of 0 until it got spidered again or whenever it is they do that. NOW, rather than delete the old, I just replace the content on that page. It keeps the spiders coming back to see what's changed and it keeps me in the search engines and my ranking on that pages doesn't go down. Of course I'm talking about changing products and themes and categories, as well as keywords and metatags, etc. So that's what I would do - just put your new content on the old page. Of course I keep adding new pages too.