Other key players: Schmitz (CB), Djourou (CB) - on loan from Arsenal until January.
Sebastian Larsson (who scores some wonderful free-kicks) and Fabrice Muamba - both began their careers at Arsenal & were both among Birmingham's most important players. Stephen Kelly started every league game (mostly at right back) - pretty rare in the PL these days.
Also a mention for Mauro Zarate - the Argentinian youngster who was pretty exciting for Birmingham near the end of the season - and in my view should've been used more. He should be playing at the top level somewhere in Europe next year even if Birmingham wont.
For the future:
Krystian Pearce - for me the best player in England's U17 World Cup team. Plays at Centre Back. Had a couple of short loan spells during the season to gain experience. Ironically Birmingham's relegation probably increase his chances of stepping into the first team.
Sone Aluko - one swallow might not make a summer so he might not be as promising as the goal he scored for Aberdeen against Bayern Munich suggests.
Jordon Mutch - schoolboy who was due to make his debut for Birmingham in the league cup this year at age 15 -but it was discovered that FA regulations no longer allow this.