i have the very simplest Garmin - the forerunner 110 with no heart rate monitor - which you can sometimes get for 100quid on Amazon. it does the basic pace measuring via GPS while you've got the watch on (I think any more information is impossible to take in - you want to just look at the watch quickly and get one stat), then lots of stats later when you can upload to the computer. at the time, i thought 100 quid was a lot, but i've worn this on every single run and, value-for-money-wise, definitely the best bit of kit I've got. there are more advanced models if you want to run intervals etc, but personally i don't...