Well Brendan, I think what's been said before about it perhaps being more advantageous just to work, earn money normally to buy and hold BTC which will hopefully appreciate over time, is perhaps the more considered orthodox view. The reason for people having this view is that smaller scale mining just doesn't offer any return on investment so they suggest that, say, rather than spending $100 on mining equipment that might never give you that $100 or any profit back, you buy $100 worth of bitcoins which has a reasonable chance of appreciating in value.

That view only takes into consideration your possible return on investment, it doesn't take into account the possibility that you might just actually want your own physical bitcoin mining rig. I, for one, love my rig and even though it's not very productive and it might never make a profit, it has taught me many things about mining and it forces you to consider aspects like which miner you'll be using, what mining pool you'll use, which wallet you'll set up to receive the fractions of coins that you get from the pool and how to send and receive coins as you use the bitcoin network to make small transactions. It gives you a sense of what it means when people talk about increasing mining difficulty and it also provides a sense on just what sort of equipment or energy is required to mine more bitcoins and that in turn helps you form a view on what a bitcoin is actually worth, which is especially helpful if you decide to trade bitcoins. Invariable you'll eventually be looking at some alternative coins (altcoins, alts) which you might get if your pool offers merged mining, or if you decide to choose to mine them later as some can sometimes be more profitably mined by the smaller scale rigs, so you'll need to use an exchange like Btc-e or Vicurex to either receive them directly into your exchange account, or trade them for bitcoins if you don't need the altcoins for any other purpose.

So although most people would say, "Hell no!" when you ask about buying a few Block Erupters, I say, "Go for it!" as even a couple of BE's will get you into the mining groove and teach you a lot and there's no end of joy tweaking your rig, adding more BE's, changing your pool, burning out power supplies, wondering which usb hubs to use, moaning about how little you actually get from mining and a million other things that you didn't count on, like now noticing how much your internet connection actually drops out and leaves your miners leaning on their shovels laughing at you rather than digging for coins while you sleep. With all that said and done, it's still a beautiful thing when a fraction of a coin appears in your wallet and you grin to yourself thinking, "I mined that". Sure your rig might not actually make back what it cost you, but if you don't think about it in investment terms, it doesn't matter. If you go out for a few drinks with friends and manage to spend $100 on beers and some food, you don't frown at the end of the night wondering where the ROI is or whether what you did was the 'right thing'. You went out, you had beers with friends, the $100 is gone and the sun will rise tomorrow.

The other thing to consider, which I'd suggest you do after getting your hands dirty and building a small physical rig, is to consider cloud mining. There are a number of options out there to build a virtual rig in the cloud, so do some research and see what is available, new facilities are coming online all the time, so the more research you do, the better informed you'll be and the more able you'll be able to make the right decision for you. Plenty of people have opinions, but the only one that really counts here is yours. Do your thing, know why you're doing it, be happy you're doing it and know that you can always change what you do later on. I have a physical rig and I mine in the cloud. I've got some new bitcoin mining hardware arriving soon but the chances are that it will be the last hardware I buy, cloud mining is just very easy and very flexible now, not like in times gone by when you had to mess around with contracts. There's a referral link to the CEX here or in my signature below, check it out so that you can see how easy it is to buy GH/s or even small parts of a gigahash, maybe you'll consider it after building a little rig, it's completely up to you.

So while the rest of this forum might tell you not to bother buying any BE's, I say hunt them down for cheap on Ebay, buy a few and get started, set up your mining software, your wallet, find a mining pool, link them all together and 'hey presto' you're now a miner. What do you have to lose? A few beers? There's plenty of time for beers

Good luck with it all.