S5 touted as world's thinnest ultrabook
New ThinkPads include business ultrabook and X1 Hybrid
High-end 13in model features Intel Core i7 processor, 4GB RAM and seven-hour battery life
Acer claims long battery life, rapid resume, and ultra-thin design for its ultrabook
High performance 13in laptop is thinner and has longer battery life than MacBook Air, Lenovo claims