This is my preferred method of showing text across a selection of cells. Use this instead of merging cells. Merging cells can play havoc with some other excel functions.
My theory about why “Center across selection” is not widely used is the placement in the dialog box.

You see it is at the bottom of the list.
This option will center the text across a selection of cells without merging any cells

AutoFill can be a timesaver if you often work with common lists of data. You can define your own custom lists and then use them over and over again, as described here.

A great timesaver when entering data is to use Excel’s AutoFill feature. To use the feature, enter enough cells that Excel can figure out how you want to fill the remaining cells in series. For instance, enter 1 and 2 into two cells, or 5 and 10 into two others, or Monday and Tuesday. Select the two cells and then click and drag the Fill handle at the bottom-right corner of the selection border.
As cool as AutoFill is, an even cooler timesaving feature is to define your own series of values that AutoFill can use. Follow these steps:

1. Click the Office button and then click Excel Options. Excel displays the Excel Options dialog box.
   Make sure Popular is selected at the left of the dialog box.
2. Click Edit Custom Lists. Excel displays the Custom Lists dialog box and hides the Excel Options dialog box.
3. Select NEW LIST in the Custom Lists list.
4. In the List Entries portion of the dialog box, start typing the items in your fill series, in the order they should appear. For instance, you might type a list of department managers in alphabetic order. Press Enter at the end of each element.
5. When you are done, click the Add button.
6. Click OK to close the Custom Lists dialog box. The Excel Options dialog box reappears.
7. Click OK to close the Excel Options dialog box.

You can now use the custom list for the AutoFill feature. Simply type whatever entry from the custom list you want to start with, select the cell, and then drag the Fill handle. Excel fills the selected cells with the items from your custom list, in order.

Here is a tip from Allen Wyatt’s Excel tips site.

Allen was asked if there is a way to selectively load add-ins for specific worksheets. He said there is a way to do this, but it involves the use of macros attached to the Workbook module for the specific worksheets. Follow these general steps:

1. Load the worksheet for which you want a specific add-in loaded.
2. Press Alt+F11 to display the VBA Editor.
3. Double-click on the “This Workbook” object in the Project Explorer. Excel opens a code window for This Workbook.
4. Place the following macros in the code window:

Private Sub Workbook_BeforeClose(Cancel As Boolean)
AddIns("Add-In Name").Installed = False
End Sub

Private Sub Workbook_Open()
AddIns("Add-In Name").Installed = True
End Sub

1. In the code, change the name of the add-ins (“Add-In Name”) to the real name of the add-in you want to use with the worksheet.
2. Close the VBA Editor.
3. Save your worksheet.

I will be using this method to choose which addins I have loaded at any one time. I have up to three loaded at one time which I don’t need all the time. Thanks Allen