I've been playing on and off for about ten years or so. I'm still a beginner - but then I aspire to play like the big names so I'll probably never get there, but I have had great fun trying. I've got a range of guitars - acoustics, semi-acoustics, electro-acoustics, steel, and solid body's (still waiting for the next one to be built). I started on a battered acoustic (and I mean battered - it was recovered from a plane crash and the neck was split and the body had a hole in). I learned to bash the chords out of that. I got a really bad imitation strat after that and a really cheap amp. That was detrimental to my playing, I'm sure. The amp buzzed constantly, the guitar just wouldn't stay in tune, frets buzzed and the fret board wasn't accurate enough (so things genuinely sounded out of tune).
If I was starting again I'd spend around £150 and get something that's decent enough quality to sound 'ok' and hold it's tune. Tanglewood, Westfield, Epiphone, Fender, Yamaha - they all make guitars in that price range. Play it. Play it a lot. Find someone else who's just starting out too. Play together. I learned really fast when I was living with someone who was also learning and it just became a competition to get better, learn more complicated stuff, learn the latest oasis number, etc. It made a massive difference.
For £150 you'll get a guitar that you could reasonably learn with and not feel that you're battling against the instrument to produce a decent sound. If you stay with it then you'll begin to realise which direction you want to go in - strat / les paul / classical / cut-away acoustic etc.
I've played on some of the more expensive acoustics and electrics (american custom strats & teles, breedlove acoustics, taylors). They were easier to play. They sounded better (mostly, although I would argue that some of the really expensive stuff doesn't sound *that* much different if at all to something half it's cost), but, the only reason they sounded better is because I had a vague idea of where to stick my great podgey fingers. Learn on a £30 guitar, learn on a £3000 guitar - you'll still hit bum notes, bugger chords up, mistime picks, and feel lost to start with.
Whatever you choose - have great fun

, stick with it and consider getting the instrument set up professionally. Stuff coming straight out the factory is rarely set up well (so the strings are a mile high off the fretboard making it harder to hit chords and notes cleanly).