Are you a businessperson needing a bit more power, intrigued by yesterday's HP ProBook s-series unveiling but not impulsive enough to spend your business's hard-earned money without a full review? Better fire up that expense report, because according to Laptop the ProBook 4510s is a solid investment. Its styling and performance get high marks, and 4.5 hours of battery life is decidedly stout for this class. The Chiclet-style keyboard was said to be a little flexible, but that full number pad is a nice bonus. The 15.6-inch, 1366 x 768 display impressed, and it's even avail