I just got my MBA 11 today and I LOVE IT. Esp. getting it for less than 700! I want to replace my giant heat producing, ear deafening tower by connecting my MBA to an external display at all times. But I worry if this sort of usage will destroy the battery in the MBA. I don't know if laptops were made to be used nearly 12 hours a day while plugged in? I love it soooo much because the MBA is virtually quiet and there is no heat blowing in my room so my room stays cool. I plan to buy the LG 34 inch monitor with ultra widescreen to enjoy it even more. But is this going to do harm? ---------- One more question. Is it better to leave it in sleep mode or shut down if I use it on a daily basis?