Mac Mini i5 (MD387) performance

I'm about to buy my first mac, a Mac Mini MD387 i5, 4GB Ram and i have some concerns. Unfortunately there isn’t a mac store in my town so i have to trust the community on this :P.

I’ve searched the forums and found similar posts but none was answering my question so excuse me in advance if this has been answered:

I work as Web developer / Designer and i want a new office machine. In my work i use code writing software, Photoshop, Firefox and Chrome with lots of tabs open, mail application and Skype. My main concern with the Mac mini is the performance with my monitors and their resolutions. My main monitor is a 24" display with 1920x1200 resolution and i have a second smaller 20" one with 1680x1050 resolution which i plan to connect it through the DisplayPort.

Will the Mac Mini perform well and fast with dual monitors and those resolutions? Will there will be noticeable hiccups or delays when i open or switch applications?