Well, I think this covers it (except for the idler/tensioner pulleys). Under $500 for everything. Not bad.

• Primary Drive Belt - ContiTech 7PK1666
• AC Drive Belt - ConTitech 4PK870
• Water Pump - HEPU P414
• Water Pump Pulley - BMW 11517545295
• Thermostat - Mahle Behr 11537586885
• Coolant - BMW 82141467704 (2 gallons)
• Water Pipe O-Ring - Victor Reinz 11517507717 (update: not necessary, included with new water pump)
• Coolant Return Pipe - BMW 11511439976
• BimmerFix Coolant Pipe Stent Kit