Its become quite common for clients to ask abstractor's to carry E and O over the last 4-5 years, I carry it myself and many of the abstractors who do my work carry it as well.
Also, most companies only require that you carry $250,000.00, they do understand that its expensive.
I got 5 quotes and ended up getting mine thru Title Industry Assurance Company they gave me the best price out of the 5.
If you decide to get it you can contact Richard Curd at 1-800-628-5136. They require that you join ALTA.
And as Kevin said, its a good idea to have it to protect yourself and your personal assets, especially if you are not incorporated.
We live in a sue happy country.