If you really want to read about some advanced categorizing check out the YNAB forums.
You Need A Budget
This is a link to a thread on categories:
Show me your cateogories! : YNAB's Four-Rule Methodology
Most of the posts here are some variation of categories by category subject - Housing, auto, food, etc. I do that myself.
However, another way to do it that is intriguing is to categorize by priority of expenses rather than subject. So some have categories like: monthly bills, irregular bills, lumpy expenses, rainy day, etc.
Anyway
my current categories with subcategories, listed after the master category:
Irregular Expenses
Auto - Fuel; Auto Repair|misc; Tolls|Misc; Auto Insurance; Auto Purchase
Food - Groceries & Supplies; Dining Out
Household - HH Repair|Maintenance; HH goods; Computer|Office; HH & Umbrella Insurance; Real Estate Taxes; Cleaning; Mortgage
Home Improvement - Electronics|Decorative; HH Furniture; Major Improvement; Major Appliances
Utilities - Electricity; Natural Gas; Water; Garbage; Phone; Internet and TV
Healthcare - Health & Dental Insurance; Medical & Dental
Personal - Clothing|Personal ME; Clothing|Personal DH; Entertainment, Financial, Fitness; Gifts & Donations; Life Insurance; Vacation|Travel; Cash Miscellaenous
Pets - Pet Food & Supplies; Veterinarian
Children - DS, DD
DH Spending - DH Spending, DH Computer
ME Spending - Me Spending, Me Computer, Me Reserve (set aside to save for future computer)
Reimbursable - Loan or Work expense; Loan - DD; Loan - DS (these are minor amounts if we pick up something for a child who pays us back for it)