Don't get me wrong - I love Irfanview, but some may be turned off by its relatively spartan interface.
If you'd like something with a little more conventional and user-friendly interface, try this one here:
FastStone Image Viewer
It's got a whole slew of options to configure (if you're into configuring options), or it works just great with the default settings. Editing capability is not too shabby either.
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