The style of table you have selected will directly impact on which chairs will work. For example, you'll often find that circular tables can accommodate far wider seats and even high backs will work well, wheres more angular designs often require compact chairs, as they'll have legs to contend with.
While upholstered seats might sound a little traditional or old fashioned, they are actually just exceptionally classic, elegant and beautiful. To modernise traditional dining chairs, grey fabric is a very on-trend choice that will never date or look anything other than sumptuous and stylish. For a really luxurious choice, deep velvets and stunning brocades should be at the top of the potential fabrics list.