go for the freshest tyres you can. check the date stamp (which many dealers change). it's a 4 digit code embossed in an oval on the sidewall of the tyre. the first 2 digits are the week it was produced and the second 2 are the year.
example:
2208 would mean the tyres were made in the 22nd week of 2008. DO NOT buy a tyre which was made any later than 4008 otherwise they'll have a very short life as they will have started getting harder than what is acceptable for daily useage.