Appreciate if someone can help. If my plan is to just upgrade to fusion drive (no CPU, GPU upgrade), would I be better off with just the base 27" ($1799) or upper end 27" ($1999)? Our family's main use for the iMac will be web browsing, social networks, document/spreadsheet editing, storing photos, music, skype, streaming youtube/netflix, and iMovie editing. If any gaming, it will be social network gaming (Farmville type) and toddler, young children learning games. Will the 3.2GHz i7 make a lot of difference over the 2.9GHz i5? Will the NVIDIA 675MX with 1GB make a lot of difference over the 660M? At last, is fusion drive even worth the upgrade for our usage? Thank you and I really value your input!