What bitcoin wallet should i use?

It depends on what you need it for. For example, if you want to use bitcoin to buy things, then you'll need a wallet that accepts debit or credit cards. If you're just starting out, I recommend using Coinbase. They have a user-friendly interface and allow you to buy and sell bitcoins directly from your bank account. If you're more technically inclined, there are also a number of other options such as Blockchain.info and Electrum. These wallets give you more control over your bitcoins but they also require more technical knowledge to use.