Which is more important to you: the difference in price or the difference in capacity? If money is not an issue, the SSD is so fast it more than makes up for the pokey processor in so many of your day to day tasks.
I picked up my SSD Air yesterday (SoHo store in NYC) and it is simply amazing. I've loaded most of my stuff, including MS Office, and still have 37Gb available on the drive. That's more than enough for a temporary home for photos, video, etc. that ultimately will reside on my desktop MacPro.
I know it's a very high pricepoint, but if you can swing it you will be glad you did. When was the last time you heard someone say they regretted getting the faster or more powerful machine?