Mods that you can just kind of have and screw around with. The most "Un-casual" I would go would be something kind of like the invasion mod. My definition of "casual" also includes mini-game type things, but what I'm mainly looking for is stuff that goes well with the MC Heli mod.
Mods that suggested mods should be compatible with(If you dont know if the mod you are going to suggest is compatible, post it anyway! :D):
i REALLY suggest Blood Magic: Alchemical Wizardry awsome mod, Or Flans mod but its a hassle to get but its awsome, they have 3D planes and guns if you get the right things :D. you get them in packs like i have: prototype Scifi V1 and stuff as i said though its a great mod (idk if its for 1.7 )
Mods that suggested mods should be compatible with(If you dont know if the mod you are going to suggest is compatible, post it anyway! :D):
MC Helicopter mod
Zan's Minimap
Hats mod
Lucky Blocks
Village Info
and lastly Damage indicators.
My mods: Archmagus, BetterBoneMeal, BetterVanilla, Brewing-API, NaturalArmors, and PluckableChickens!