There isn't a stat recorder for Halo 2 PC, but the MonstrMoose team have one set up just for their servers. If you play in the MonstrMoose servers often then you can view all of your stats here:
http://monstrmoose.com/player_stats.php?player=
Just type in your gamertag and you can see how many kills, deaths, scores, headshots, K/D ratio, and all of the medals you have gotten. Here's mine for example:
http://monstrmoose.com/player_stats.php?player=kael573
Only hitch is that if you have not played on the MonstrMoose servers, you will not have any stats.