Coinbase or wallofcoins to buy btc. Poloniex is my favorite platform to trade on but have accounts with the big 3 in the US and bitshares.

I also have the gunbot for daytrading. It earns me a few percent a day on my investment. If you are interested in the gunbot it costs . 1btc but there are some used ones for sale and referrers can get you a discount. https://bitcointalk.org/index.php?topic=1715214.0