My personal opinion is that your question depends on what you need/want from Bitcoin.
If you want to buy things with it then go with a mining rig (although other than a cheap deal on ebay, ASIC is the only longer term way). It baffles me when I hear people complaining about the high price of Avalon #3 when it would appear to me that a 3mth ROI would still be possible at a network hashrate of 175TH/s and a 6mth ROI at 355TH/s assuming a price of $50 per BTC! When was the last time you saw an investment that paid for itself and then went on making money after less than 6mths?! If you only spend the Bitcoin you make then it is almost irrelevant what the exchange rates are.
If you want to make big money then you and me need to invent time travel and go back to when BTC was $5 and the Avalon guys were shopping around for pre-orders... but first we should go forward and see if BFL ever ship
As for currency markets, I am less familiar with this side of it, but from what I have read there are people who say this is a bubble that will inevitably crash and others that say that BTC has been under valued for so long this is just catching up. Consult a psychic, flip a coin... if you can predict it accurately then I certainly wouldn't share how with anyone! lol
I grew up on a farm, cash poor but asset rich... so I will always go with the option of buying an asset that may have some value later (ie. the mining rig).
Anyway that is just my 0.2BTC