Format Factory is exactly what you would expect it to be, a converter that works wonderful.

The UI is easy enough, just drag and drop the file into the space area-thing and it will ask what format you want it in. Press "start" and minimize it, stare at it, whatever, when it's done a little message pops up saying everything is done and how long it took.
The customizations is good enough to keep you happy, different skins,

It can also read DVDs and ISOs, as well as some minor editing.

List of Formats:

Video

MP4
AVI
3GP
RMVB
GIF
WMV
MKV
MPG
VOB
MOV
FLV
SWF

Audio

MP3
WMA
FLC
AAC
MMF
AMR
M4A
M4R
OOG
MP2
WAV
WavPack

Picture

JPG
PGN
IOC
BMP
GIF
TIF
PCX
TGA