Simple question -- If a transaction remains as 0/unconfirmed for long enough in the Bitcoin-QT wallet, will it eventually delete and return the money to my BTC balance?
If your client sent the funds, no ... never, at least not automatically.
Other nodes will eventually push that transaction out of the way to make room in the memory pool for more recently received transactions. At the same time, your client will sporadically (e.g., at least once an hour) notice that the transaction has not confirmed and will re-broadcast the transaction to its peers. Those other nodes that have pushed the transaction out will re-learn of the transaction when it gets re-broadcast.
