I would suggest looking at the software that came with your camera for RAW conversion. I don't know what camera you use, but a large number of Nikon users will use the NX / NX2 software to convert RAW to TIFF and then use that for further editing. I have found that free software is often worth exactly what you paid for it.
I will use DxO for lens correction, as it does a better job than the Adobe software, but it is certainly not free and am a great fan of Photoshop, but it is rather pricey.