Maplins and PC World were both nice to browse the aisles of, if only to keep up-to-date with what was available in affordable tech and gadgets. But I guess those days are gone, and the best options now for Stokies are:
1) For electronic widgets, sockets and wires too big for the letter-box, eBay's arrangement with the Sainsbury's Argos facilities. This allows the buyer to collect eligible small-packages from Sainsbury's Argos counter in Stoke. Although the time-out on that can be a bit tight, and if you don't get there sharpish after you order then you'll find "it's been sent back, duck".
2) For basic things like a new computer mouse and keyboard, and the occasional January Sale blink-and-it's-gone bargain, the nearest best option is probably the Office superstore on the eastern edge of Festival Park. (Update, it closed in spring 2019.)
3) For PC owners and courier-phobics, who need something more substantial and delicate (a new hard-drive, monitor or even a new PC), the best local alternative option is probably now Overclockers in Newcastle-under-Lyme. Overclockers are a well-regarded national PC-centric gaming hardware company, with HQ and public counter and display-space on the outskirts of the town. They make some good value gaming PCs, and have just this month taken the plunge into making well-reviewed graphics workstations for home office-based artists, graphic designers and 3D animators.