Not long ago Lexar released a 128GB SDXC media card (I have this card) for under $200 dollars. Currently I use this card as my featherweight external hard drive, doubling the hard drive space available in my Macbook Air. SDXC is a backwards compatible format to work in cameras that use average SDHC, but does not suffer from the 4GB file limit (your camera must also support this). Yes, it does work in every camera i've thrown it into including the Sony HX9V, Fuji X10, Canon S100, T2i, 60D, etc. Although each of these cameras still bottleneck with their own firmware limiting file recording.
Recently released is the new Sandisk 64GB SDXC media card and at first glance you'd think the Lexar was a better deal when it comes to Size/Price ratio, but the new Sandisk is Speed-Rated to UHS Class 1 standard spec'd out at 95MB/s Read/90MB/s Write Speeds, while Lexar's SDXC is still rated as SDHC Class 10 133x 20MB/s Read Transfer. Might be overkill for DSLR shooters, but big Video camera shooters can take advantage of these larger and faster SDXC cards. The new Sandisk 64GB SDXC cards are already available via B&H (click here)
Sandisk new UHS Class 1 64GB SDXC Media Card