Here is the ultimate bag... someday... maybe... if I won the lottery or received some other windfall of disposable income.
Prada Vitello Daino North-South Tote Bag $1,750
Coach has some great tote bags:
Coach Legacy Leather Tanner Tote $498
The regular size Tanner Tote above would hold everything I needed but I love, love the Mini Tanner because it has a crossbody strap as well as the small handle. It is super cute but probably wouldn't fit my iPad. Also it comes in colors like mint and coral that are great but if I'm paying this much, I want the bag to be in a classic color so I can use it for years and years.
Coach Legacy Leather Mini Tanner $258
If I were to go the less expensive color route, I really like this one from Gap:
Gap Flat leather tote $98