What kind of bike / riding? MTB knobblies or 23mm road tyres?[/QUOTE
Everybody will recommend what they use themselves, so advice will be a bit biased, but for what it's worth, I have used continental city contacts 28mm on my winter road bike.
http://www.wiggle.co.uk/continental-contact-ii-reflex-city-road-tyre/
Have tried swalbe marathon +, but the tight fit and splitting on the side walls have turned me off them.
Contacts are about £17, so good value as well.