Ah every gadget freaks dilemma what to choose the ipad or the iphone, well i prefer the ipad over the iphone i will specify my arguments & reason below.
Iphone is one of the best phones available on the market with 225,000 apps for iphone it leaves competition far behind (next in line android has only 70k apps),
we certainly regard iphone as the best smart phone in the market & that's it.
Ipad however is something you can't put in a category, it isn't a netbook or a laptop, it isn't just a ebook reader, according to me ipad is in a class of it's own, you can't really categorized it .
It is one of the best device to read books & pdf but it's also one of the most unique platform to play games on, it's best web browsing experience hands down(yes i know it doesn't have flash , but see android with it's horrible flash support).
When ico said the ipad is just ipod touch with bigger screen, he wasn't wrong but that doesn't make it a bad thing, instead of it makes it one most compiling reasons to buy the ipad in first place, the 9.7" LED screen feels so perfect when you watch movies on it, when you browse on ipad you just tap you don't even think about it, you just do it.
The Performance on Ipad is just awesome, everything feels so snappy let me give an example when you draw something on ipad using the brush app, the software & hardware keeps up with your finger it feels like you are actually drawing it.
Reading books on ipad is so awesome it's closest to reading on actual book as with touch screen it feels you are actually reading a book, did i mention ipad is absolutely best device to read comics on till date ?,it's one best way to read news, it makes news fun all over again. Also games are in HD compare to other devices (iphone,psp,nds) so when you play games like racing HD on it using accelerometer it feels like actually holding the steering wheel to control the car, it feels epic.
Also when you are going to bed want to see some TV series or catch a film on your bed, why would you want use for itouch or iphone for that when you can get best of both world using ipad, the movie experience feels so nice, with over 50k apps made for ipad already in the app store & all the 225k iphone apps can also run on it so you will always find apps you need.
You can buy the iphone & be satisfied cause it's a very good smart phone but you can buy an ipad which provides some of the most unique experince i had in years, so for all these reasons i whole heartily recommend to buy the ipad preferably the Wi-Fi (32 gb) version but if you can pay the 3G costs then i would advise you go with it.