That's really weird, i dont use so many services and i only have 10mb free or less, show me "ps" command please, that way i can understand why your services use so few memory.
total used free shared buffers cached
Mem: 127400 124860 2540 0 77440 20412
-/+ buffers/cache: 27008 100392
Swap: 2851508 22128 2829380
Maybe that's because i use a large MySQL database and i increased to the double my PHP memory and SQUID cache.