As mentioned above, an ExpressCard slot would be the most elegant solution for Apple to add versatility without adding weight to either the Macbook Pro or Air. I am still firmly with Windows and recently got a tiny but mighty Lenovo X220 with gorgeous 12.5" IPS display (two SSD's 128GB and 300GB, 8GB RAM, i7-2620M processor). I use ExpressCard 32 or 54 adapters to add Firewire, additional USB 3.0 ports, CF ExpressCard card reader, eSATA, etc. Tethers nicely with my P65+ and weighs only 2.9 lbs.