Right, i'm definitely going with Polar but there are quite a few to choose from so i'll tell you a bit more about my goals.

My fitness regime includes the following in no particular order

Interval running ie 800m x 4, 100m x 4, 50m x 4
Weights complexes ie deadlift, military press, squat, bent over row in a circuit format, low weight, high intensity
Strength workouts ie circa 5 reps per exercise
Endurance, circa 15 reps, 30-60 seconds rest per set
Possibly some swimming
Bodyweight exercise circuits

I tend to mix these up frequently so that i don't get stale, yet the endurance weight circuit is done 3 times per week at the mo.

I'm sure i've seen some where you can programme in an exercise then the weight, sets and reps for it too but not sure of the model.

Also, good places to buy them from, ie cheap?