Bitcoin value should go up because it can be used to make anonymous, untraceable transactions on the internet. There is really no other way to do that right now. Only a small fraction of people (us) even know about bitcoins. Demand will definitely go up. Supply is limited. Price going up. Yay! Any professional economists to confirm?
Being able to buy socks and toothpaste with bitcoins won't make any difference for the value of bitcoin. People can just use $'s for that.
Was going to bold some of that text, but its all relevant.
Once the price becomes more stable (as it seems to be doing) and converting BTC back to your local currency becomes more transparent to the user, then more people will take advantage of holding bitcoins for virtual transactions as opposed to paying service, transaction and exchange fees charged by the current organizations.
The price will not go anywhere near $30 for a while, as the network is over saturated with miners (like myself) who still need to cash out to cover hardware and electricity costs. Once mining becomes no longer profitable, then we will a drop in the influx of cheap bitcoins, and so long as as they become more widely accepted, then we will see their value slowly increase.