Visual Studio 2005 (and 2008 EDIT: and 2010) has a great tool for fixing the tab stop values on any form, and it's point and click! With your form open, use the 'Layout' toolbar and click the 'Tab Order' button.
All the controls on the form now have a numbered blue box near them. This number is their 'TabOrder' value and indicates the path the cursor will follow when the user tabs through controls on the form. To change this order simply click on the boxes in the proper order.
There is one caveat to all of this, container controls have to be included in your order if their children are to be included. In other words, if you want a control contained in a 'ControlBox' to be the third stop on the tab order, the box has to be the third stop and the child control has to be the first stop in that box (actually indicated by 2.0 in the preceding image). Of course, don't worry about numbering items that do not require a stop on the tab order, since their tabstop property should be set to false (labels and so on).
That eliminates another tedious task in Form development.