I've said it before, and I'll say it again (probably, nasty habit of repeating myself).... Take a look at
pocketfms Its an NMEA moving map GPS that runs on a PDA. You can run the program from a PC also to help with flight planning, and it will produce a PLOG for you (built in E6B equivalent). Basically they seem to have (colour) mapping and elevation data for most FIRs in the world. The only real pain in the bum is that you have to download the map data for each zoom level that you require (broadband required). However, its donationwear - apparently you get better detailed maps for a donation of 50 Euros and I think thats for life, they send you a serial number that you put in the software. It is in the process of being developed and is at version 0.9.49 Beta, but seems pretty solid to me at the moment.
The best thing is that you can try it out thoroughly first before shelling out the 50 Euros to see if it suits your needs.
I was considering the memory map option, but having to fork out 49 quid for new charts seems a bit steep to me compared to this.
Oh, yeah, and when you do a "direct to..." on this, you can specify avoiding certain types of airspace, so it'll route you around it automatically - which I think is a really cool feature.