You didn't mention which camera you are using, but as mentioned above the classical best choices are the
Tokina 11-16 for wide angle and
Nikon 10.5mm f/2.8 for a fisheye.
If you are on micro four thirds, you have better options:
- Olympus 12mm f/2 is much better than the Tokina 11-16
- Samyang (Rokinon) 7.5mm fisheye is much better than the DSLR version
The usual Samuang 8.5mm fisheye for Nikon or Canon is quite bad wide open. It is ok if you are on a budget, but I'd advice investing your money in a better lens than this.