Company Range of parts Shops / Outlets/ Location
Golledge< Crystals, Oven and TC Crystals and related UK
Jaycar< Test, Components, kits, Automotive, gadgets Australia, NZ, UK
Maplin< Test, Components, Computer, AV, Tools, Gadgets UK, Dublin, Galway, B'town, Belfast, Cork, Limerick
Conrad< Test, Components, Computer, AV, Tools, Gadgets Germany
KUHNE electronic< RF Modules and Kits up to 10GHz Germany
Mini-Kits< RF Kits and parts Australia
Radionics< Components, Tools, Test gear Dublin, UK as RS Components
Farnell< Components, Tools, Test gear Dublin, Worldwide Newark &CPC<
Donberg < Repair/Replacement parts, manuals Donegal
Wouter< PIC parts, surface mount adaptor PCBs, Components Netherlands
Helmut Singer< S/H Test Gear, Military Gear, Transmitters/Receivers Germany
Down East Microwave< Microwave Gear USA
Dektec< DVB modulator PCI cards Netherlands
Digikey< Components Worldwide<
Hills Components< Computer, AV, cables, connectors, adaptors UK Trade Only
Sinequanon< Surplus Connectors, cables, components UK and on eBay
Barend Hendriksen< Kits, Components Netherlands
Bits box < components UK
Sellweb ltd < components UK only in MS Internet Explorer!
Magenta Electronics < Kits, PIC, Parts UK
Tech Design < Kits, Components Belgium (English)
Elektronicksoustky< Components,Coilcraft Czech (English coming?)
Byvac< Displays, adaptors UK
Toby Electronics< Connectors UK

eBay based suppliers tend to be more specialised. Check prices as they can be more expensive OR much cheaper.
Read Descriptions and Postage charges carefully. Check Data sheets.
Mostly anything that transmits is illegal or can only be used on Amateur Bands with a Licence.
Not Purchased means I don't know how accurate or fast they are, as I have not used them.

Ebay sellers (your own risk) Supplies Possible Location
943componentsupplies< Varies. Toroidal Transformers UK
axminsteraxminster< Workshop tools UK, good postage
Bitsbox Electronic Components< Components UK
eeedesigner < Parts, Gadgets China
Fast Components < SMD starter kits (Good Value), Zener Diodes, Small Motors UK
PW-ELECTRONICS< Components (Nice range & price) UK
AMTOOLS-UK < Toroid cores, Components, Tools, Aerial parts UK
sure electronics < LCD Modules, Tools, Components, Rotary Encoder China
the oldmans shed < Balsa Wood, Modelling UK
NEOGL< Radio Control Models & parts, Components China/HongKong
MobiComm< ATV modules. WARNING  (Not Purchased)
L-M-ELECTRICAL< Domestic repairs UK?
chinaelectronicsdirect< Gadgets, Computer accs. China or Hong Kong

WARNING : Only the 1.2Ghz is legal, and it needs Licence. The 900MHz units are USA ISM band only and Interfere with GSM phones in Europe.

Various adaptors
USB to TTL Serial<

Serial Bluetooth about $7 with Free Shipping from Goodluckbuy< in China

Serial Bluetooth Module <

I'm reminded of this Supplier I bought regularly from. In I think Odessa, Ukraine.
He now has his own website too<
He still has the Ebay store<
Everything well packed.
I've bought giant ferrite rods, valves, rod pentodes and strange glowing things.