looking to buy my first tablet. My wife has an ipad 2 , however, I am looking at spending less money. If I bought a samsung galaxy tab 2 10 with 8 gigs. Is it worth the extra money to buy one with 16 gigs instead of the 8 and adding an sd card. Don't know what an sd card is for. Is it straight storage? All I need a tablet for is internet surfing, email, facebook etc. Also play words with friends game from Zynga. Do I need more than8 gigs?