Getting a new computer, how fast does my pentium need to be, how much RAM, etc?

For example, I can save 400 - 600 bucks by getting a 1.8 Ghz pentium with 1 gb of ram and not the 2.2 ghz pentium with 2 gb of ram. All I do is surf the web, listen to music, and use word/spreadsheets. Sometimes I do picture and video editing but not extensively. Is it really necessary to go top of the line? What is the bare minimum I can sc by with?