I second what others say about Skydemon though I myself have not bought it. I have been using Airnav Pro from the App store which is an option if you must have the CAA charts instead of Skydemon's. This does the job for me until I have enough pennies for Skydemon.
* [probably] MemoryMap if you only want the CAA charts / moving map
* Air Navigation Pro for something a little more sophisticated based on the CAA charts that allows for flight planning and navigation
* RunwayHD is a step up again including airspace warnings, live NOTAMs, weather etc.
* Skydemon don't use CAA charts, but it is arguably the most sophisticated GA aviation nav app in the European market right now (and will have airfield plates in a couple of weeks time)
FWIW, having got used to them I find Skydemon's charts preferable to the CAA charts (amongst other things they're vector diagrams so the words etc are always the right way up whether you want to fly north up or track up), controlled airspace is only shown in a band around the height / altitude the flight is / is likely to be conducted at, the plotting of NOTAMs and weather is incredibly useful, and the live navigation including airspace warnings makes flying with it very easy.
SkyDemon on iPad3 has been perect for my needs - realtime NOTAMS/METARS/TAFS, graphical profile of intended route, automatic FPL filing (free if flying through R112 during Olympics), automatic W&B calcs, endurance calcs, flight logging, etc. etc. I used to use a Flymap L with scanned 250000 and 500000 CAA charts, but the vectored SkyDemon charts are MUCH better. Take the 30 day trial - you'll sign up within a week
I have an iPad at home and an iPad on the aircraft panel. I have both sky demon and runway HD. I use one ipad for home planning (along with browsing and angry birds!) and the other for nav. Prior to using SD I always had an airspace aware and garmin 496 (which remains as my backup). Now the garmin seems horribly dated. I have been enjoying using SD but have had a nagging feeling that I was missing the official CAA charts, particularly because I could glance at the GPS and then find my place on the paper chart easily.
Well... Last night for was my first fly with runway HD instead of SD. Conclusion: it's much worse than SD. The CAA chart can only be north up, it's cluttered, it doesn't zoom without being unreadable. Contrary to my expectations it seemed old fashioned relative to SD. In addition, what's with the puke green aircraft? anyway, back to SkyDemon for me having properly sampled competition. And the latest SkyDemon even has a couple of new features I emailed Tim to suggest! Great software, great guy.
I think a lot of cheap GPS products gave the CAA charts (which are IMHO the best VFR charts in Europe) a bad name, by displaying them on small screens, which is virtually useless because you can't see most of the airspace labels.
The smallest screen on which the CAA chart is readable is something like 8" to 10" - assuming 1:1 i.e. a real 500k scale.
I find they work fine on an Ipad, though the Ipad version of MM is a crap app.
Also I use the current-1 version of MM because in the last one they have somehow crippled the ability to run old QCT charts. With the version before, I can just drag/drop QCTs into MM's Documents directory using Iphone Explorer. This gives me access to potentially hundreds of 1:25k and 1:50k O/S maps which are widely available as QCTs.
For European VFR, Oziexplorer will open the way to running VFR charts for all of Europe, but the IOS version has been a long time coming...