You can buy the 8800 separately from apple (it's not officially listed as an upgrade for the current models, but the card works just fine in it), it might be backordered right now, not sure. There is also the ATI 3870hd, but I haven't personally tested this card, all the tests I have seen seem to say it is quite close in performance to the others.
http://eshop.macsales.com/item/ATI%2...ies/100435928/

The OCZ drives are great for the price, there are a number of models available, you want a CoreV2 or newer. They are 2.5", and to mount them, you need this adapter...
http://www.maxupgrades.com/istore/in...product_id=180

here is one of the drives
http://www.newegg.com/Product/Produc...82E16820227411