Here's a short list of those suppliers of electronic components that I use most often, plus a few tips, if you're in Switzerland.

Note that on imports, VAT below CHF 5 is not charged. Given a VAT rate of 8% this amounts to a tax free import on all purchases below CHF 62.50, including shipping. Swiss Post will charge an extra CHF 18 on top of VAT as a cash-on-delivery fee if VAT is due. With DHL or UPS you only pay VAT (i.e. no extra fee). Keep that in mind if you order and/or choose your shipping provider. In summary, try to keep your orders below CHF 60 (as a safety margin) if you must use the postal service, and/or choose a different shipping provider for orders above CHF 60.

USDYou can make them bill you in CHF or EUR, but USD is cheaper! No minimum order, but shipping fee quite high (USD 30). However, no shipping fee is charged for orders above USD 100. No customs duties, but VAT payable by customer on delivery.
EURNo minimum order. Moderate shipping cost (EUR 18). Components are slightly more expensive than Mouser's. No shipping fee for orders above EUR 65. No customs duties, but VAT payable by customer on delivery.
EURNo minimum order. Very competitive prices, especially for ICs, potentiomenters and knobs. Ships with general postal service or DHL (VAT payable on delivery). See import note above.
USDVery cheap, especially "value packs" and ICs. Ships using postal service from Hong Kong (slow). See import note above.
BG Micro
USDRare items. Ships using postal service. See import note above.
CHFExpensive. No minimum order. Package and delivery CHF 12.80.
EURInexpensive. No minimum order. Package and delivery EUR 12.80. Ships using DHL.