I used to have a Reebok i-Run.
Basic, no fancy features, (didn't connect to the net, run apps etc) but it did what was needed.
You could choose special programs for resistance etc if you wanted, but what I liked was you could just get on, hit start, and go for as long or as short a spell as you needed, going faster or slower at the touch of a button, and it would give you a full breakdown at the end of distance travelled, time taken, calories burnt., average heartrate etc etc...
Simple and effective. Recommended.
it was kinda like
THIS, but an older, more sturdier model.
Edited to add, it was nice to be able to have it on a gentle setting, so I could stroll while watching TV etc. Keeps you active and moving, even if your not doing a 'workout' per say...