MSO 2K7 runs fine on our older desktops and our "middle of the road" laptops (not the fastest available, just new).
A few words of advice from someone that's supported laptops (& the idiots toting them) for the past 15+ years...
- Do NOT spend anything more than $100 on a used laptop! Anything more will just cost MORE when it dies or breaks mid-semester. Plan to spend another $100-150 for a standalone USB drive to use as "backup" for when it dies and harp on the virtues of "back up NOW, back up OFTEN".
- Watch the fine print on NEW laptops! While many can be had for $400, they also just have a 30 DAY warranty. Something that's opened/closed repeatedly, lugged all over campus, & generally banged about WILL NOT LAST. While these "cheap" laptops may be cheap enough to purchase new every 1-2 years, the time & anguish spent over trying to recover data or retrieve files (ONLY happens when the deadline is looming over you!) ain't worth the price. Many vendors offer the equivalent of "accidental death & dismemberment" coverage. This isn't cheap but will cover any damages, whether accidental or deliberate...