2 workbooks of Excel.
Book 1 is cash flow -- income in one column, expenses in the next, credit cards in the third (these get paid off monthly in full, but I track them for cash flow so I can make sure they are covered each month). There's a column tracking the savings account, as well. The last column is the math that tracks the total balance. The spreadsheet is projected out 4-6 months and tied out to the bank statements weekly(-ish).
Book 2 is a net worth tracker, updated quarterly. This includes bank balances, 401k balances, Roth IRA balances, credit card balances (at the time), home mortgage, etc. I've also included an estimated home value so I can track equity, but I don't include that count in my net worth calculation even though I could / should.
Fairly simple, but I've never run into a cash flow problem, have upped my savings amount and grown my net worth every quarter since I've started tracking it 3 years ago so it works for me.