My 5 cents :)
* Spread - good to be tight, but this is not so important as execution. With other words even if you have narrow spread, but execution is bad and always with slippage, then the spread you see does not worth nothing!
* Scalping - is not more risky than long term trading, just requires proper mental attitude. The trades are lasting seconds, or minutes, but in the EOD you do not have open positions and you do not have market risk transferring overnight (what about major news came out, earthquake in zone of the currencies traded, flooding, unusual events came out ... etc.) :)