look here,
http://www.cabelas.com/cabelas/en/common/search/search-results1.jsp?_dyncharset=ISO-8859-1&selectedPerPage=&hasJS=true&_D%3AhasJS=+&_D%3Asort=+&sort=all&Ntt=waders&_DARGS=%2Fcabelas%2Fen%2Fcommon%2Fsearch%2Fsearch-box.jsp.form1&Go.x=35&Go.y=7
best company to buy from, order and enjoy. I fish for a living and wear foul weather gear and waders daily and have tried several brands, this store has always provided me with excellent service, even replacing a set I sent for repair, they had a the hole in them was from an oyster reef, my fault, no questions asked, got a new pair a couple of days later. For metal detecting I would try a boot built in style, easier to get on and off. The separate boot is more comfortable in the long run, they have less foot fatigue, however you have to take all that crap off and tie your boots, dry your boot etc... A pair of boot combo you wash them, hang to dry and pack them up. Depending on where you live, I would buy the medium weight and a few layers under them, that way if it is warmer you wear less clothing, in the summer lightweight clothing, you stay semi dry and water does not make you loose too much body temp. In the winter I use a dry suit, wear polar fleece under them and I stay nice and dry even if a wave hits me high or I slip and fall, waders fill up fast. When they do the fun is over.
Have fun, buy a good pair don't be cheap. A good pair will last years, a cheap pair will let you down.
Eric