Arne,
Not to despair! That extra 100 watts could be the difference between something working and something not. for instance, my blender will work on the 300 watt inverter, but not at the top speeds. With 400 watts it would. That could be the key difference between a really smooth smoothie and a lumpy one!
Also, that tire inflater will come in handy one day. I went out and bought a separate unit at Sears for emergency purposes (I don't carry a spare for the trailer).
I got my panel at Solar Electric Inc. in San Diego
http://www.solarelectricinc.com
They have some really good deals on all sorts of factory-second PV panels (still warrantied). I got one of the Unisolar 32 watt (2A at 16V) flexible panels.
The cool thing about this type of panel is that it is unbreakable, you can roll it into a pretty small radius and store it away, you can attach it to just about anything, and it has an extra low profile (very thin). The Unisolar panels (including their rigid panels) have a series of internal diodes that allow the panel to keep producing current, even when partially shaded. They do have a lesser output for their size than some other panels, but they do work in partial shade, unlike some others. And of course, the flexible panels are a bit more expensive, but not outrageously so.
Rik