All in all, I really think you will benefit from the upgrade to Illustrator CS5. It has something for everyone. Even if you don't plan on creating a perspective masterpiece, you can always use a faster way to be able to get your work done.
Brian Wood is a seasoned web developer and web/print technology trainer. An Adobe Certified Instructor in Acrobat 9 Pro, Illustrator CS4, Dreamweaver CS4, InDesign CS3, and Photoshop CS3, Brian has authored several training books, including Adobe InDesign CS2 Hands-On-Training, Adobe Illustrator CS5 Classroom in a Book, and others, all published by Peachpit Press. He has also authored online training videos for Dreamweaver, InDesign, Illustrator, Acrobat, Expression Web, and other products.