Does anybody have any pointers toward the best deals for the N900 at the moment?

Quidco currently have 10% cashback at the Nokia store, and a couple of smaller online stores have it for slightly less than £450. But if I add on a SIM-only deal for 12-18 months, my costs are pretty similar to a subsidised handset bought via, say, nokiaretail (mobile phones direct).

I'm having trouble getting the price below this line. Annoyingly, it's only now that I spotted quidco's 20% cashback + 10% voucher deal they were running in January! How often does Nokia issue new discount vouchers, and is it worthwhile waiting?