I really, really think you need to stop listen to what all these (i'm sure, well meaning) people keep telling you and just write your own thing - the reason soooo many personal statements are pretty much the same, and therefore unorigional, is because everyone listens to what people who 'know better' tell them to do. I'm of the opinion that if you sit down and work out exactly what all the reasons are that you want to study philosophy and why it's o interesting to you, then just write it in a coherent page of writing, if you want it enough your enthusiasm will shine through the page anyway. Obviously it's probably prudent to pointout how what you do relates to your subject, esp if there are any particularly good examples of commitment (a philosophy/debating soc or something... dunno), but other than that, you have free reign - it's your statement!
If while you're writing it and you have any particularly crazy ideas, write them down, and don't dismiss them just explore them and see what people think.
In the end, thousands and thousands of people write these every single year, and while some definitely stand out more than others - better written, interesting idea/format etc, the likely hood that you're gonna come up with a really original idea compared to all the others the admissions tutors have read, is pretty darned unlikely, so i'd go for enthusiam every time.