I think mixing it up with a green chino would be awesome. Jeans are always a good stand by, but I really love these marc jacob green chinos and think that they would be a great fit!

http://www.blue​fly.com/Marc-by-​Marc-Jacobs-dark​-green-cotton-st​raight-leg-chino​s/cat60015/30102​3202/detail.fly?​referer=ca_froog​le&cm_mmc=ca_fro​ogle-_-na-_-mens​_casual_pants-_-​301023202&mr:tra​ckingCode=34B013​D7-E581-DE11-B7F​3-0019B9C043EB&m​r:referralID=NA

accessorie wise I think keeping it simple is best since polo's are known for being casual. A simple scarf or hat would be great!
hat:
http://www.urba​noutfitters.com/​urban/catalog/pr​oductdetail.jsp?​id=18127506&item​description=true​&navAction=jump
scarf:
http://shop.obe​yclothing.com/p-​1227-charter-sca​rf.aspx
OR
http://www.saks​fifthavenue.com/​main/ProductDeta​il.jsp?PRODUCT%3​C%3Eprd_id=84552​4446240049&afsrc​=1&site_refer=GG​LBASE001&ci_src=​14110944&ci_sku=​0810305014585
OR
http://www.poly​vore.com/mens_ar​ab_scarves_cotto​n_scarf/thing?id​=3010093

The great thing about polos is their versatility. While jeans are the obvious and classic choice to pair with a striped polo, I can see why you'd want a few more options to choose from. For pants, consider rocking a pair of khakis or even some nicer slacks if you want to dress your shirt up. As far as accessories, a leather or woven belt, a messenger bag, a killer watch or my favorite- a cool leather cuff- would do the trick. You also might want to consider layering another, slightly longer shirt underneath your polo to add some interest and give your outfit some depth. When it comes to choosing shoes, a polo can easily be paired with flip flops, sneakers, or dress shoes depending on the occasion. Hope this helps!!