Currently I am running the Michelin LTX M/S and they are great tires but starting to wear out. I really don't want to spend the amount it would take to replace these with more of the same, so I am looking at the Yokohama Geolander HT's. The Michelins are 235's and I'm looking at going to the "standard" size of 225 with the Yoko's. Will I see much difference in handling/ride by doing this?

probably not-i thought standard size was 235/75?? well thats for 15" rims but........

Some X's came with 225/70/15s.

If you want to stick to a stock size, go with 235/75/15.

Alec - And these would fit on the existing wheels that currently run 235/70/15 Michelins?

Yes.