Robilar's Gambit is always nice for more attacks. It's in the Player's Handbook 2. It says whenever a character with the feat is attacked, they get an Attack of Opportunity against their attacker.
It requires 12 BAB and Combat Reflexes, but that's it. (Combat Reflexes would of course be required to get multiple Attacks of Opportunity per round and use the feat well).
Very good feat for a tank. It means that things which try to kill a character with the feat die quickly. And if your friend takes feats outlined in the Tom of Battle for Dummies Handbook which make her character into a "Lockdown" or even "Crackdown" Crusader/Fighter, things the character fights will be forced to attack them (and die). Full Attacking this character would be especially suicidal.
Here's the link to the Tome of Battle for Dummies handbook which is from this forum (yay!):
http://brilliantgameologists.com/boards/index.php?topic=357.msg6904#msg6904For class suggestions:
Go a mix of Fighter and Crusader (which sounds pretty good). Taking two levels of fighter fixes the Crusader stance progression as others have mentioned. This is because 1/2 of levels in non-martial adept classes count as Initiator Levels for qualifying for having enough Initiator Levels to take high level maneuvers and stances. Because the Crusader always grants stances one level before they actually qualify for their new stances, 2 levels of anything else bumps up their Initiator Level by one and thus fixes th problem.
I'm getting off track. Go Fighter for more feats if wanted, go with more Crusader levels for more Crusader abilities and maneuvers/stances. Never, ever take an odd number of fighter levels, however. Fighters only get feats at even levels and that is the only reason to ever take levels in Figher. I would suggest at most 4 levels in Fighter. 6 or even 8 might be cool, but probably not as optimized as possible.
For a prestige class, I will again heavily recommend going all 10 levels of Eternal Blade (Tome of Battle p109). It gets maneuvers/stances as a Crusader and has access to the best martial disciplines. It's tenth level ability cannot be replicated by any other Fighter-type prestige class that I know of and is awesome. My first post describes it.