Rather than linking every single one of these on all of my cards, I thought I'd share with you the basics of what I use for card making.
Fiskars Paper Trimmer
I use this for basic card base cutting as the line it cuts is nice and straight, and the blades last a long time. I'm also considering buying a guillotine trimmer so I can cut through thicker items or multiple sheets of card stock.
I used to have the larger version of this, but it was too unwieldy on my craft desk to grab - this smaller version is much more convenient. I use this to create the folds in all of my card bases, or any other scoreline needed (for example, creating patterns on backgrounds). It comes with a scoring tool but I prefer to use a teflon bone folder to emphasize the creases. The plastic bone folders can sometimes leave marks which don't look nice!