Block out jets for $50.

Affordable Creative HN 700 Noise cancelling headphones block out jet engine noise! read more 

It is now 2011 and this is an old review so you might want to check 
the new 

Ambient Noise Cancellation Inner Earphones, they will run you about $100 and Pioneer claims the will block out 90% of the ambient noise. Now word on whether the will block out the noise from your annoying neighbor.