Newegg is running month long Black Friday deals, I received the first email this morning. They have a couple of good deals on 16gb SDHC cards. the A-Data 16gb is $26.99 with free shipping. It is a class 6 card, I have had one of these for over a year with no problems. The other is a Patriot LX for $29.99 shipped with an $8 mail in rebate (one per household); this is a Class 10 card. I opted for 2 of the Patriot LX's for my K5, seems like an appropriate time for an upgrade!
Here are the links:
New Egg - Patriot LX 16gb Class 10 New Egg - Adata 16gb Class 6
(note, the adata card is listed at $29.99 if you go directly to the website, the link above is only through the deal page, which itself is only linked via email. The Patriot card is $29.99 directly at the website).