I use faststone
FastStone Image Viewer, Screen Capture, Photo Resizer ... for handling photos once I have converted them to JPEG.
It's a really fast viewer and will view RAW,JPEG etc but I use it mostly fopr batch converts of files (you can convert to a fixed size based on the longest side so all your landscape/portrait shots end up the same size.
Dead easy to use and does loads more and is free (he just aks for a donation if you like it.....and I did so I did)
Martin