Mining solo is a perfectly valid choice which is quite underrated. I'm mining solo with my 6 usb erupter simply because I don't care about the small profit I would make with pool mining.
So I rather take my chances with solo mining. The biggest share I found so far is only 8.5M but I don't loose my hope, and it's fun to check every morning if there is a "surprise".
Obviously I'm also still fully contributing to the bitcoin network, whether I will mine a block or not.