Garment/suit bags work well, and another very good option is the 'Stuffed Shirt', which I have seen for sale at John Lewis in London. Depending on the one that you choose you can pack 1 - 3 shirts/blouses, a tie, belt, underwear and toiletries in a very compact space without creasing. http://roadwarriorgear.com/rwg/luggear.html is a US site that shows them/sells them, and Woodruffs of Winchester http://www.woodruffs.mcmail.com/indexa.htm also sells them (UK) The versions available from these two sites are slightly different (nylon vs cotton, & more expensive in the UK)

I also like the 'roller' type luggage, which can be *carried* on board as hand luggage. Different companies again offer different versions, but a lot include a garment bag/shoe compartment, and there are even some with space for your laptop. (I like this...)

Choosing your clothing wisely also helps to minimise/disguise creases - knit fabrics obviously crease less, & dark, textured or patterned fabrics don't show mild creases. If you want to minimise space/weight, socks & underwear can be used to maintain shoe shape, & always pack the heavy items at the bottom of your luggage - place your linen shirts on top of everything else! Folding crease-prone clothes around sweaters/t-shirts helps to soften the creases, and if you must fold a jacket fold it horizontally, not lengthwise - the creases will be less obvious & 'hang out' much more easily.

Finally, if you don't want to iron, hanging clothes in a steamy bathroom helps to get rid of creases, & in the case of dire necessity, dampen the crease slightly & use a hairdryer to 'steam' it out.