Yapbam (Yet Another Personal Bank Account Manager) is a portable cross-platform Java-based personal finance manager.
Getting started is relatively easy. An Import tool might be able to import your transactions from another account manager or your bank's online statements. An Entry Wizard helps you manually enter everything else, and automatically generates any regular transactions.
The program then monitors your balance, raising alerts whenever it's negative, and producing various budget and category-based reports to show where your cash is going.
Yapbam's Java code runs under Windows, OS X and Linux. If you do have multiple Yapbam installations then the program can also synchronize your data between them via Dropbox.
Handy extras include a currency converter which can grab the latest rates from a couple of online sources, while optional password protection keeps your details safe from snoopers.
A well-designed personal finance manager, easy to use, with plenty of features, and still being regularly updated and improved.