A shade over budget but its good enough quality , and will work well with your processor
The mb even has onboard gfx and that will keep power demand low and hopefully let you run it on your psu till you can upgrade psu and gfx
The RAM you picked has much looser timings . The spec says it has CAS timing of 6 . The one I listed has 4-4-4-12 , which means it does in 4 MHz what your selection takes 6 Mhz to do . Even though they are both rated at 800 MHz your selection is WAAAAY slower .
Shipping on RAM wont cost much . Its small and light .
If your processor came with a heatsink and its all new then you wont need thermal paste . There will already be a patch of paste painted on the heatsink.
Asrock is a good budget brand , and it has the same good onboard graphics
If you are planning on gaming your case wont do. It has one small fan in the back and wont shift enough air to cool everything . The coolermaster has two large fans in the top and back .
But you are right the hec will do for basic needs .