I'm not super familiar with OS X (having migrated recently from a windows machine to a mac) but it seems odd that I only have 3.7 GB of 8 GB free while running no applications sans activity monitor. Is this normal behavior under Mavericks?
Yes it's completely normal. Kernel_task is the operating system. On my system, kernel task uses 2GB-3GB of memory and this is fine too since the amount of memory it uses depends on the system workload and other various factors.
Also in mavericks, free ram is wasted ram (as it should be) so OS X tries to use as much ram as it is possible to speed up performance. I have 16GB of memory and I currently have 4GB free, meaning the system is taking up 12GB of memory with only Firefox and iTunes open. Again, this is good and it means that the system is caching everything to run more efficiently.
As long as your memory pressure stays below red, you don't have to worry about memory.