I've been plowing through Bennett's Introduction to the Gothic Language. What a great book! I found it so easy I was surprised to read Thiudareiks' description of it as for someone more than a beginner, but I guess I'm no longer a beginner at Germanic languages...even though I think I'm still a beginner at Gothic.

Anyway, the main thing I like is its organization. It's not a textbook, but it's definitely not a dry, dusty grammar like Joseph Wright's books (which, btw, are very useful books; they're just not the cover-to-cover type). The best thing about Bennet's book's layout is: it gets you reading Gothic right away! From the beginning, each chapter has:

1. a reading in Gothic (from Scripture, since all extant texts are of Wulfila's translation of the Bible);
2. all the vocab you need to understand it;
3. a manageable-sized description of some piece of grammar (say, a couple of classes of nouns here, a few more the next chapter) with exercises to help you drill yourself on verb conjugations, noun declensions and such; and
4. some other information.

These last sections vary a good deal, and could almost be gathered together to form one story about the Gothic language. They range from an easy-to-read discussion about Indo-European to the place of Gothic within the Germanic language family, to a brief history of the Gothic tribes, to (later) discussions about phonetics and morphology that are more technical, not b/c of its writing style but simply b/c it's packed with information.

These last sections stem mainly from the book's expressed purpose of presenting Gothic not only as easily as possible for the learner, but in the context of comparative Germanics and comparative linguistics generally. If you're not into that, you don't need to know it to learn the rest, it's just a very versatile book. In fact, a decent amount of effort on each chapter of this book will amaze you with how soon you can read Gothic texts. Highly recommended.