CF or SD? pros and cons of each?

I'm considering making the transition to professional photography, currently using a nikon d80. I love everything about the d300, and the only thing holding me back from buying it is that it takes cf instead of sd cards. Since I have a large collection of sd cards, I'm hestitant to make the switch. Several people I spoke to have told me that cf is decreasing in popularity and eventually will be phased out. That leaves me wondering why nikon would make the d300 in a not so future friendly cf format. Or am I missing something? Are cf cards better for professional use than sd?

CF cards are what all the pros use. They are literally explosion proof, drowning proof and even in my case washer/dryer proof

Make the change and enjoy a new D300. There is an adapter you can buy so you can use your existing SD cards in it.

When the CF cards were first designed, they were built to withstand 20,000 formatting cycles ... or over 50 years service if you formatted them every day. In practice, they are the best for professional use for many reasons; contacts are internal, so sticky fingers will not cause problems, large enough not accidentally loose, eventually available in sizes up to 120GB and all of them (at this point) come in faster write times than any other memory cards and as preciously mentioned, nearly bullet proof.

I have 14 of them, 1GB, 2GB and 4GB.

I don't think they'll be gone anytime soon.
Most professional cameras use CF. I think they have been around longer than SD and they are be a little faster and cheaper.

Compact flash cards are inherently superior to SD cards in that they have built-in controllers which allow them to be used in legacy devices up to the limits of the file system (2 GB in FAT; 8 TB in FAT32).

There are a couple of drawbacks to Compact Flash cards:
1) they are larger than SD cards
2) the host device has pins that are easily bent if the card is inserted incorrectly.

SD by comparison actually has had to have changes, with a distinction being drawn between the original SD cards and newer SDHC.

CF is certainly not decreasing in popularity, in that it's the card used in the two best Nikon cameras, the D300 and D3. It's also the card of choice in high-end Canons too.

Many CF cards are metal bodied too, much more durable than the plastic body SD cards (I have an SD card in my phone and the plastic has already broken on it).

So, don't make your decision based on SD vs. CF. It will be the least expensive part of making the change, especially if you've ever bought a lens or a flash. Make your decision on whether the camera will offer a feature you don't already have or do what you want it to do that you can't do now.