Keeping track of trades

right now i am keeping track of all my bitcoin related trades using an openoffice calc sheet. it has several sheets for various transactions, e.g. transactions between specific exchanges or transactions to and from an exchange and my bank account or from an exchange to a personal wallet and so on. for all transactions it takes the respective transaction fees into account and shows the actual net amount that arrives at the other end.
it also features some "tools" like a profitability calculator for arbitrage related sequences (buy on exchange X1 for price P1 with fee F1, sell on exchange X2 for price P2 with fee F2, payout to bank account with fee F3). i enter the amount of BTC i buy and sell and the current exchange rates for EUR and then it tells me the actual profit i get after all fees were subtracted.

on an overview page i have to enter the EUR exchange rate manually and then it will show me my current profit, if i would sell all bitcoins i currently own. it also shows the lowest exchange rate i would need to sell at to make profit, how much money i have invested in total, how much BTC i own (and how much of the BTC are currently on which exchange accounts or wallets). it also contains some informational values like the number of BTC and EUR moved in total or the sum of fees i have paid for all the transactions.

i have searched for available software that would support similar features. what i came up with were a few online services that could partially do those tasks and a software called BTC-Trader. the software isn't free and online services i simply don't trust enough to give them my trading data, even when they merely require a username, password and mail address for registration. even if the owners provide the services with good intentions they might get hacked and lose that data...

my question is whether anyone knows a software that supports the above mentioned features? it should be free and obviously open source, otherwise it would have just the same problem regarding trustability.
so far my calc sheet has served me well but it gets bloated more and more as i am adding features (already 12 sheets in that file containing lots of different formulas and tables) while manual work such as having to enter the current exchange rate manually are annoying, which is why i have started to search a software tool.

as i am a software developer i am thinking right now about writing that software myself, it would be free and open source and written in C#, tested on both Linux with Mono framework and Windows with .NET framework. but my time is limited and before i start to work on this i wanted to make sure there is nothing i am missing and i am doing work someone else has already done.

also i am very curious how others are doing it, are you are using similar solutions or you just don't care for such things and trade solely relying on your gut feeling? do you track your trades? and if so, to what detail level?