I once had 50+ hacks installed, but I eventually decided to go ahead and upgrade to 3.5. Unless you like spending loads of time upgrading each time a new vB version is released, you should upgrade to 3.5 and enjoy the "magic" of what plugins can do! Sure, not every hack has been ported to 3.5, but you'll find several familiar (and new) hacks you can install without file edits
As for customized styles, vB3.5 offers a template comparison tool. At worst, you could just revert templates like forumdisplay and threadbit and begin using features like inline moderation instantly