So... Wife is traveling, Monday is San Valentin day here in USA and she asked me today if instead of flowers, chocolates and all ladies stuff, an iPAD

... Hmmm..
With 2 Kindles and a Galaxy Tab, have "no moral right" to say no. Anyway, budget is not an issue here but she gave some options. Of course another gadget would be fantastic but with so many readers I will start to feel myself like a hoarder besides I'm not a big Apple's fan (sorry, I'm just being honest)
My questions would be: if I sold my Kindle DXG, can I side load my Oreilly mobi books into iPad? And if thats possible which ereader can I use, Kindle for iPad? Similar question would be for my ePub books.
If I jump into Apple's waters I want to be sure I can read my PDFs and SQL books Before selling my Kindle DXG.
Thanks in advance,