It may not have the universal level of use that Word does, but if any program is worthy of the title of second fiddle then it's Excel. Anyone who has worked in a vaguely corporate environment is almost certain to have come across this most delightful of tools in some form or another and likely come to dread it - unless you're an accountant and wish to conform to the stereotype.
It is unfortunate that, because of an Office-wide change mentioned on the first page, the exact market Excel targets is likely to be the same market likely to avoid this particular version. I am of course talking about the omission of VBA from Office, and thus Excel, in 2008. Speaking as the ex-employee of a large government body, I can attest as to the reliance of organisations on the flexibility and power of VB compared with just plugging formulae into cells. Basically, if you're considering Excel 2008 for your Mac-based employees and they need to use VBA-laced spreadsheets then re-consider. In Excel 2008's defence, most people in this situation will be tied into a Windows environment anyway - stereotypes exist for a reason don't you know.
Happily if the above isn't an issue for you then you'll be more than pleased with the upgrade over previous versions of Excel. As with Word the Ribbon makes an impressive début and brings many useful tools into an easier to reach place, probably also making said features more likely to be used in the first place. As with Word the Ribbon's layout of templates is much nicer to use than the method employed previously. Whether for whole document layouts, such as invoices or accounts, or if you're creating charts, the previews offered from the Ribbon make it a much easier and intuitive task.
For casual users of Excel, or the self-employed, the new ledgers will be a real boon. Not only do they make it easy for a first time user to create a professional looking document without needing a professional IT qualification, but they should also be of benefit to current users who want to repurpose the time usually wasted on producing a decent looking document and put it to the better use of making some money. Yes, long term or heavy users will probably have templates in place already that they wish to repurpose but for everyone else it's a helpful and welcome addition.
As with Word, the formatting pallet again shows its strengths; enabling you to easily edit sheet and chart properties without delving through reams of menus. My favourite example is changing the colour and style of a worksheet (or a single element) from a side menu with a single click. Also in the same toolbox is the Formula Builder, which as you might guess offers a list off all the formulae in Excel, with a handy search function and Recently Used list. This enables you to construct complex calculations stage by stage, with helpful explanations of what each addition will actually do accompanying each. It sounds like a simple premise but if you aren't entirely familiar with the intricacies of every calculation Excel has to offer it could prove invaluable.
Whether for better or for worse Excel 2008 is a fairly big shift away from the dull corporate-types-only application it might previously have been perceived as and all told the changes are for the better. Okay, culling VBA will affect the hardcore business Excel users the most and, when it comes down to it, they are really the main market for the program. However, as I've already suggested such a user is more likely to use Windows anyway and thus removing the corporate look and making Excel all the more inviting to the average Joe is no bad thing by my reckoning.