i will be purchasing the 15in PB shortly. as you probably know, it comes with 512 of Ram standard. I am thinking about upgrading it to somethign more. do you think i need anything more than the standard though? i am a trypical user: email, internet, office, occasional web design, gaming, and light photoshop use. is 512 enough for this or should i get the 1 gb? also, should i upgrade through apple or buy seperately from crucial? thanks.