Buy a Tablet vs a laptop?

I am considering these two:

HP Pavilion dv5t
-Intel(R) Core(TM)2 Duo Processor P8600 (2.4 GHz)
-4GB DDR2 System Memory (2 Dimm)
-250GB 5400RPM SATA Hard Drive
-512MB NVIDIA GeForce 9600M GT
-15.4" diagonal WXGA High-Definition HP BrightView Widescreen Display

HP Pavilion tx2500z
-AMD Turion(TM) X2 Ultra Dual-Core Mobile Processor ZM-82 (2.2 GHz)
-4GB DDR2 System Memory (2 Dimm)
-160GB 5400RPM SATA Hard Drive
-ATI Radeon(TM) HD 3200 Graphics
-12.1" diagonal WXGA High-Definition HP BrightView Widescreen (1280 x 800) w/Integrated Touch-screen

My main concerns are that, the tablet has a 12.1" screen. Is that too small? and....The graphics card for the non tablet is very good, and the processor is good also. Is the tablet capability a worthwhile trade off? (the prices are basically the same)