Did you see lots of writes or only lots of reads? An antivirus software should mostly read data from the SSD and not write much. Reading from an SSD doesn't wear it but writing does.
If you're not happy with AVG for whatever reason, let me suggest a superb alternative: http://www.microsoft.com/Security_Essentials/. Microsoft Security Essentials is very low on resources but still shines in tests/benchmarks.
If you're concerned about how much writes occur to the SSD, please see this post for tips: http://communities.intel.com/thread/8107?tstart=0
+1 for above post.
I've been using Microsoft Security Essentials since I moved to Win7 and I think it's really good. Very simple clean interface, it picked up and dealt with a virus I had (I tested it on a known file), and it's free to genuine windows customers. Takes probably 50% longer to do a system scan than Symantec but, it works and its free.
Update: I really like MSE. It's clean, simply, and does the job. Thanks for the tip!