Is it cost-effective to purchase an expensive card? I was considering purchasing the Monarch BPU 300 C or the 600 C.  However, neither of them are expected to ship before February of 2014 or later.

If this calculator is to be trusted, it doesn't seem like one could ever earn back the cost of either of these units, especially if this difficulty graph is accurate.

According to said calculator, the 600 model would leave you $2000 short after 6 months at a purchase price of $4680.  Also, the cheaper 300 model would leave you about $1450 short after 6 months after a purchase price of $2800.  And those figures are assuming you start using the product in mid-February.  If Butterfly labs are late on shipping the cards, and you start in March... forget about it.

I'm fairly new to the Bitcoin game, so can someone tell me if I'm wrong about this?  Is it actually wise to purchase either of these cards?

Edit - The short answer is NO, especially for SHA-256 currencies.  I spent about $1000 on a 50 GH/s miner.  It generated about $30 per week in gross profit, but the net profit was less due to pool fees.  Also, my electric bill rose by $100 per month.  Luckily, I was able to find someone to buy the miner from me on ebay for CLOSE to what I paid for it.
For $2800 (the price of Monarch 500GH/s, as of 23 Dec 2013), and $4680 (the price of Monarch 600GH/s, same date), you might as well purchase a 1TH/s mining hardware, such as from VMC, or CoinTerra.

The other alternative is to use these mining hardware to mine some other altcoin, instead of Bitcoin, and hope that the other altcoin would come to prominence one day, instead of bitcoin. 

The answer to your question is that unless the difficulty drops, it is no longer cost effective to purchase mining hardware.