The lightweight, easy to move and use for quick jobs, trimmer I have is a Westcott Titanium Personal Trimmer. (
I also wouldn't be without the "Westcott 5" Titanium Non Stick Scissors" and another couple of sizes of the same thing as they are great for cutting sticky foam tape, etc.) For big batches of card making I get out my bigger one which is a two in one guilotine and rottery cutter from Purple Cows. Like -
this one - although mine is a slightly different model in a different colour. The two sids can be detached for working with just one method of cutting if the large cutting/measureing area isn't needd. This gives the flexibility of perfect straight lines with the guilotine, and the option of different style cuts and scores with the rottery cutter side, and three blades come with it. But I've also got a "
Freestyle Mouse Cutting Kit" which comes with lots more rottery blades which are fully interchangeable into the 2 in 1, giving me the options of lots of different style edges as straight cuts when in the 2 in 1, or making decorative wavy edges in the Freestyle Mouse.
GG