The debug.log posted by Hal on the sourceforge list on 10/Jan lists blocks up to 49. There's posts by two more people in January.

Buying from a local seller should be the fastest way, but they will charge a higher rate than the exchanges, especially with the recent volatility.

Not completely. The time has to be long enough for every node to verify the block. 10 minutes was chosen by Satoshi as a compromise between network security and confirmation times. In hindsight a smaller value might have been better, but not much smaller. With older versions of Bitcoin it sometimes took over a minute before every node received the block, and there needs to be a wide margin for safety.

Fees serve two purposes, to pay miners for securing the transaction record and to prevent transaction flooding attacks.

If you send transactions that look like spam - frequent and small values - other nodes in the network refuse to relay them unless you include a fee, and the transaction won't even be seen by the miners.

There's a limited amount of space for transactions in each block, and miners prefer transactions that pay the most fees per kilobyte. Feeless transactions will still get mined, although it can take hours or even days if there are lots of higher-priority transactions waiting.

The wiki page https://en.bitcoin.it/wiki/Transaction_fees has the detailed rules for calculating fees

Bitrick's series of articles https://bitcointalk.org/index.php?topic=41718.0 should be a good starting point. I don't think there's anything more comprehensive other than the source code itself.

The blockchain is currently about 6.5 GB (see the chart).

The bitcoin protocol doesn't require everyone to keep the full blockchain, however. It would be enough to keep an index of unspent transactions which is still less than 200 MB. Bitcoin version 0.8 only saves the block files to be able to seed new nodes joining the network.