For hall and kitchen, pick a colour that is very neutral, then you can have pretty much any colour units, paint etc. My kitchen/diner/utility are done with a plain rosa coloured tile, kinda beige. They have a slight sheen to them and are warm to look at, don't look grubby how ever manky they get! and go with stainless steel appliances and different types of wood - no bother. The hall is a wishy-washy pink layed in a brick pattern, (to disguise an unusua shaped hall)
Bathrooms are different in that you can go for a theme with your tile with plain accessories or (the way I went for our main bathroom) plain white tile livened up with a border. My main bathroom is 1/2 tiled on the wall with white ripply tiles and a black, grey and white border - floor is mostly white with black tacos and a grey tile around the outside. Paint colour on the top 1/2 of the wall is like blackberry yoghurt, towels etc to match.
Sky's the limit when it comes to tile, price wise. We went for the best that we could afford at the time. Always try and buy 1 or 2 boxes more than you think you'll need, you can always return them - then you are assured that all tiles will be the same shade. Luckily for me hubby is well handy and tiled everywhere, if you're not that confident it's worth paying a professional - would be a shame to pay all that money and be disappointed with the results.