You need a small frame likely 15" thru a 17" for your height. Your weight does NOT matter whatsoever. There is No "best" except for the bike that FITS you the "best". At the $600 price range you will get a fairly decent hardtail bike for that money. Here is my take on a bike: http://www.performancebike.com/bikes/Product_10052_10551_1061252_-1_400308_400001_400329 or this one: http://www.performancebike.com/bikes/Product_10052_10551_1074126_-1_45500_20000_45503 or any of these (except full suspension) : http://www.performancebike.com/bikes/CatalogSearchResultView?catalogId=10551&storeId=10052&langId=-1&sortBy=iphrase+relevance%2f%2f0&searchType=categoryId&searchTerm=400308&beginIndex=0&pageSize=16&ipState=c0%3di%253A1%253B1%253Biphrase%2bbundle%2btaxonomy%2bid%2bfrom%2broot%253B400308%253B%253A400308%253B1%252C1%253B0%26q%3d16%26a1%3diphrase%2bbundle%2btaxonomy%252F%252Fv%253A0%26a0%3diphrase%2brelevance%252F%252Fv%253A0%26i%3dsitemap%2bid%26k0.0%3d400308%26qt%3d1249389137%26qid%3dqmjyB19cBwZtu%26vid%3dvSLU93PgPMXUv%26ioe%3dUTF-8%26s2%3dsitemap%2bid%252F%252F1%26qtid%3dnmjyB19cBwZtu%26s1%3diphrase%2brelevance%252F%252F0%26rid%3drq7pCwaH5UjVP%26s0%3diphrase%2brelevance%252F%252F0%26t%3d0%26m0%3diphrase%2bbundle%2bid%26mcmode%3dtest&cn1=f03%2f%2f400+-+600%2f%2fp%2f%2f0%2f%2f15%7c%7c&categoryId=400308
