CPC are still around, part of the same group as Farnell these days. Their actual component range is limited although prices tend to be good on the stuff they do stock. Their strength is in electrical commodities like IEC cordsets, where their pricing and availability are very good for a traceable supplier. I use all of them, RS, Farnell, CPC for different reasons. Audio and video stuff I get from Canford; their catalogue prices are sky-high but with a trade account they are hard to beat.
Not sure about the best way to buy small quantities. Cricklewood Electronics have a reputation for being friendly and helpful with small orders but I don't know what their range is like, as I only use them for a few specialities. There's an incentive not to shop around when one needs to maintain turnover on a trade account. eBay can get you out of a hole for some obscure and obsolete parts, but there are many items that I absolutely would not buy from an untraceable source because of the percentage of fakes. Certain semiconductors are almost guaranteed to be fake unless traceable under a QM system. Some will work but not to spec, others will be dead, or a different part, or whatever. Sometimes the higher cost of the pro suppliers is well worth paying.