They're both pretty good CPUs, with the i5 having an edge in performance. Part of the extra cost of the i5 system will be for the better video chip.Passmark CPU benchmark scores
T2050 @ 1.60GHz = 762
Core2 T6600 @ 2.20GHz = 1385
Core i5 450M @ 2.40GHz = 2516
What is the price differential between the two systems?