Panasonic have on display at CES 2010 a roadmap of memory cards that they are working on along with their potential speeds. What's interesting to see here is at the top right of the page you'll see a 2TB memory card which is quite an achievement (see larger version of the image below).
Although the 2TB card is still a way off, the 1TB card should be with us towards the end of this year. The new memory cards fall in to a new category called SDXC cards and will start at 48GB in capacity moving up to 64GB, 128GB, 256GB, 512GB, 1TB and 2TB variations. The previous cards known as SDHC show as having a speed of up to 22MBps. The newer SDXC cards unfortunately don't show the speed although it is indicated that the speed will increase on these new range of cards. The specifications for SDXC do show possible speeds of up to 104MBps so it shows what potential these cards can actually reach.
The main question after knowing when these cards will be launched is how much they are going to cost you. I expect that when launched the 1TB card isn't going to be cheap although in a few years time the prices will dramatically drop. An alternative option could be a 1TB laptop drive although hard drives don't really offer the protection and security of memory cards.