How many times will you use the speakers for listening to music on a mobile phone? It's the quality through the headphones that matters. And W800i (or even K750i, for that matter) beats the pants off Nokia 6270 in that aspect.
You cannot connect Nokia 6270 to speakers of your own too. And if you connect W800i to half decent speakers, they will make Nokia 6270 look like an April Fool joke (which, pardon me, I think it is anyway)!
And the only thing that Nokia scores in against Sony Ericsson is softwares and that aspect is not present in Nokia 6270. There are VERY few softwares available for 6270. You should definitely opt for the Sony Ericsson W810i.