
If your project calls for large amounts of Kreinik or Glissengloss Rainbow blending filament, or if you just like to have plenty of bling in stock for adding to projects, consider Madeira no.40 (sometimes to be found in the "machine thread" category). It works exactly the same as Kreinik or Glissengloss (in fact Glissengloss is a Madeira thread too, and has the same colour numbers...), but comes in 200m spools at £2 each (from Tandem Cottage). Doubled (using a loop start) and used for full cross stitch it gives good coverage on 18ct and 16ct.
It doesn't come in as many shades as the other two (you can see a shade card here: the top one of the two is the blending filament), but at 200m I wouldn't recommend getting it in shades you use only once or twice anyway -- however it's great for "basic bling" shades, light & dark gold, silver, white/pearl (equivalent to the much-used Kreinik #32), and possibly black and copper.
As a comparison, if you wanted 200m of Kreinik (4 spools) it would cost you £6.44, and 210m of Glissengloss (6 bobbins) would set you back £7.62...