The SSD will still be available for defragging manually if you really want to. What Windows 7 should do, is remove it from the defrag schedule (so it won't get defragged automatically)
So, if you run the defragger (eg %windir%\system32\dfrgui.exe) and click on Configure Schedule and Select disks, does the SSD drive appear there? (It shouldn't).
Re prefetch and superfetch.
How do you know they are enabled?
As I understand it, defragging an SSD can shorten its lifespan (and so you don't really want to do it regardless of the speed of your SSD) whereas prefetch and superfetch are normally disabled on fast SSD's because they don't provide any benefit on fast SSD's and not because because they cause problems.
From the Engineering Windows 7 team (see http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx )
Be default, Windows 7 will disable
Superfetch, ReadyBoost, as well as
boot and application launch
prefetching on SSDs with good random
read, random write and flush
The implication is that it will enable them if it thinks it helps.
What sort of figures do you get if you run HDTune (http://www.hdtune.com) ?
Was restoring from a win7 generated system image a mistake? Am I getting optimal SSD performance?
Can't answer that question, but I can point you to Paragon's blog Misaligned partitions are a problem for SSD's (Note, they sell a product to re-align your partitions)
See also here
I must confess, I am still running with a mis-aligned partition. I keep telling myself that one of these days I will try Paragon's program to see if it makes a difference, but have not got round to that yet.