I believe that preassessment serves as a powerful tool to gauge student's readiness for a new topic or unit. Whereas diagnostic tests give students the opportunity to test out the very material that they will be learning in the unit, good preassessments involve testing students on the topics that they have learned and understand, which translate or are more developed in the new unit. Preassessments can also involve interviewing students, pulling answers from their funds of knowledge to gauge the student's out-of-school exposure to the topic.
I also believe that formative assessment not only checks the student's progress toward understanding the learning goals, but serves as an excellent indicator of the effectiveness of the teaching that is being done in the classroom. Formative assessment reveals misconceptions and understandings, and should be used as a means to plan reteaching and enrichment.
I believe that summative assessments are necessary to see student understanding as a whole. I enjoy giving a range of summative assessments, from traditional fill-in-the-blank or multiple choice, to oral interviews. Students also should be given opportunities to choose assessment projects of various nature, that involve application of all of the topic's learning goals.
These are a sampling of some of the assessments I've used specifically to test fluency, vocabulary and other literacy skills, judge progress, assign reading levels, and hold literacy mini-conferences, etc. I used Fountas and Pinnell assessments to gauge student reading skills this year.