7Zip is the coolest compression tool I have seen, and the best part is that it is FREE! Check it out at www.7-zip.org.The interface is pretty nice, but the format support is just awesome. It even supports .iso images.
Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR
Unpacking only: RAR, CAB, ISO, ARJ, LZH, CHM, Z, CPIO, RPM, DEB and NSIS