To be honest, I've read through a lot of this thread and there are some interesting comments and points of view but there are also some quite clearly inane comments coupled with a generous helping of bitterness.
I think that the main points that seem to have fallen out of this are:
(1) No-one in either the lower or higher tax brackets are saying that they don't want to pay tax.
(2) The majority of those posting feel that there is a social responsibility to pay tax to support those less fortunate.
(3) Higher bracket tax payers don't necessarily have as much disposable income as lower rate tax payers; however, unfortunately it would not be possible to means test every earner in the country and so blanket policy must prevail.
(4) Higher bracket tax payers feel they are already paying enough tax, especially given that many have paid for their own further education and are still paying for it.
(5) Lower bracket tax payers think that it is fair for higher bracket tax payers to pay more tax, as they earn more money. However, once again consideration is not given to disposable income.
(6) An element of luck is often attributed to higher level tax bracket earners being in the position/job that they are in now. Mainly people have focussed on "good luck", without consideration that some may have been motivated to succeed by a run of "bad luck" or circumstance.
Given consideration for each of these points, I think the only thing that we can conclude is the fact that this is not an easy problem to solve. The mere fact that lower bracket tax layers are calling for a higher burden to be placed on the higher level tax payers demonstrates that there is at least some grounds for feelings of inequity... however, the source or genesis of these feelings is pretty hard to pin down, other than people are bemoaning their bad luck etc... despite there being no consideration for the fact that we may create our own luck, at least to some extent.
I think from my own perspective that my own opinion is that the tax banding is probably okay where it is now. I don't think the bands should be moved, raised or lowered. I think that looking a tax in isolation is the wrong thing to do. From a macro economic perspective you could almost draw a parallel with looking at tax alone with short term profit maximisation in private enterprise. It would be a short-term measure with limited immediate benefits but with the potential to really harm the longer term objectives of creating wealth on a nationwide basis. Rather a holistic approach is required which will closely scrutinise public sector spending and how tax funds are spent.