My own personal opinion is that the 410/510 are both aimed at the entry level user
I lean towards Riley's view that the E-510 ranks abovethe entry level. In addition to the points he makes, I would add the observation I've often made about Oly digicamsthat they're the only ones I know of which allow you to change (especially reduce) the defaultcontrast level recorded by the camera. This is very important for photography in bright sunlight where you are able to capture a broader luminance range (at the expense of having to then increase the contrast manually in PShop for each shot). However I do appreciate that this may not be such a big issue for folks living in the British Isles <grin>.
The dual flash card feature is very handy when you're in situations of strange or unusual lighting because you can store good previous photos on one card and use them to evaluate the current situation with the camera's - bynature an uncalibrated - LCD screen. This is not a feature likely to be used by beginning amateurs.
My E-500 has been used a lot in dusty desert conditions (although not battlefield conditions) and itsdurability has been exemplary, so I'm feeling that for me the E1+ would need to offer an awful lot to justify spending twice the money over the E-510. But that's just me...