The age old beginners question of which type of guitar should I buy to start off with, is best answered by asking yourself which type of music you want to play. Here is a brief lowdown and the points to look out for when choosing a suitable acoustic.
There are two main categories here - acoustic and electric guitars. Acoustic guitars are great for accompanying yourself singing in a singer-songwriter role and also can be used in a band situation for "virtuoso" style group playing, say in a soloing jazz style. Electric guitars are mainly used in a band or group situation for guitar solos and rhythm work.
The description "acoustic guitar" covers all types of guitar, designed to play and sound without further or necessary amplification. They come with either steel or nylon strings. Steel stringers sound very much different to their more rounded and mellower cousins. They can be heard on all types of music too, from Pop to Elvis, to swampy old bottle-neck blues licks, to the mighty Travis. Great for banging out moving tunes or dropping it down to subtle finger-style chicken-pickin'. They are versatile to say the least, and the most common amongst bedrooms I would imagine.
Nylon stringed guitars are typically suited to and heard in Classical, Spanish and Flamenco style music. For a wonderful example of nylon-stringed magic check out Paco De Lucia or John Williams. These guitars are also to be heard in many other popular styles, such as Sting's wonderfully simplistic but effective fret work, in the well known and beautiful song "Fragile".
Tip: If you want to play traditional classical or flamenco style guitar, get a good graded teacher ASAP.
An important point to note here is that strings are the lifeblood of any guitar so make sure to invest in a quality brand at all times. Start off with a set of medium gauge (12s or 13s) and see how you get on. The heavier the gauge the more "body" in the sound. The price? Harder on the fingers to play but you get used to it. A typical medium size acoustic set would contain the following size strings in a set.:
E string .013
B string .017
G string .026
D string .038
A string .048
E string .058
Experiment over time until you find a good set that suits YOUR style. Go with a respected brand-name such as "Martin" or "Fender".
Acoustic guitars can also be amplified on stage and recorded in various ways if desired or necessary. The simplest and most direct way is to mic them up with a microphone or install/stick on a pickup. Acoustic/Electro guitars as their name suggests, are simply acoustic guitars with the ability to plug into a suitable amplifier. This just means that they can be heard over say, a noisy pub racket of cheering...yeaahhh. Normally this feature is used for live gigging. In the recording studio it's usual to use the studio's recording facilities to capture a guitars sound to tape. It's far superior, but feel free to experiment in your own time.
A good tip is that when looking out for an Acoustic Electros, or a "Semi-Electric" as they are also commonly called, is to make sure that the guitar sounds great un-amplified as well as great when plugged in. If the guitar sounds weak un-amplified, chances are it could sound weak amplified too.
Also watch out that your chosen guitar has a nice playable "action". This relates to how high the strings come up off the fretboard. A cheap and badly made guitar has a very high action, and is therefore very hard to play. This is to be avoided like the plague! If you simply lower the action on a cheap guitar it will buzz and fret out (not sound)
all over the place. And so onto Electric guitars which we can have a look at next - in the meantime happy strumming.