Garmin 305 and 310 are both great Garmins models. read info on this site and inform yourself well before you buy:
http://garmin-305-review.com
http://garmin-305-review.com/garmin-305-vs-310/
Buy Garmin 305Forerunner at best price at Amazon:
http://www.amazon.com/Garmin-Forerunner-Receiver-Heart-Monitor/dp/B000CSWCQA/ref=as_li_tf_ssw?&linkCode=wss&tag=mirjamitropho-20
Buy Garmin 310 Forerunner:
http://www.amazon.com/gp/product/B0025VKW5K/ref=as_li_tf_tl?ie=UTF8&tag=mirjamitropho-20&linkCode=as2&camp=217145&creative=399377&creativeASIN=B0025VKW5K
