The i5-2500 has the Intel GMA 2000 integrated graphics (The K-Series chips get the GMA 3000. Don't ask me why Intel did it this way, it makes no sense) but it will support Dual Monitors, although not well. A $50 graphics card would be way way better. Unless your idea is to use the Intel QuickSync (I think thats what they're calling it) to encode video. I read a few weeks ago that Lucid was making a chip that would allow QuickSync to be used with a dedicated graphics card installed but I haven't seen any reviews yet.
I think you are getting confused with what part of the name matters. I assume you are getting an Asus P8H67 Family Mobo. The numbers you are looking for are the H67 which denotes the chipset. But to answer your question, the H67 chipset will allow the limited bclk adjustments but not multiplier based overclocking. Additionally, the H67 chipset seems to limit ram speed to 1333mhz.
Hope this helps.