The second card is a great idea using the Lovely Letters Alphabet set to stamp X's and O's across the card. You could also spell out "LOVE" or another short word as your sentiment for another occasion or a person's name. She used the definition from the Define Your Life set but the Valentine definition from the Valentine Defined set in the Occasions Mini Catalog (page 9) would also be wonderful for this card design.
The third card is another fast and easy card that has a lot of impact. She used a strip of Real Red DSP from the Pattern Designer Series Paper Stack shown at the top of page 175 of the big catalog. This pack is wonderful, 40 sheets of DSP available in your choice of all 4 color families as well as the In Colors for 2010/11. This is a great way to get a lot of double sided DSP for a better price.