I'm just coming to the end of a two year deal with vodafone and I'm fairly underwhelmed by what they have to offer to encourage me to stay with them.

Current phone is a Nokia Xpressmusic 5800, 100 mins, 300 texts, no internet deal for £15 a month.

Now for me to stay in the same price range, the phones on offer are crap, no better than what I already have, but the leap from that level to say an HTC Desire S is a tenner more a month, which I'm not prepared to pay.

So am I been unrealistic in wanting a decent deal on a Desire S or can they be more 'flexible' when they think they are going to lose a customer?

You need to find a deal you like the look of on another network that offers what you want before calling Vodafone. Doing this will gioe you an idea of what you can realistically get from your provider. Rember, they are a business and will not want to give you anything they don't have to.