For Anglo-Saxon/Old English literature, if you don't have time for Beowulf, you might enjoy teaching the Battle of Maldon, a short account of a battle between Anglo-Saxon and Vikings, which depicts Anglo-Saxon war culture, loyalty and leadership, sacrifice for one's society.  Two other short poems, Widsith and Deor, give students a broader view of Anlgo-Saxon world view and expose them to the blend of pagan and Christian beliefs often expressed in Anglo-Saxon literature.

It is difficult not to use Chaucer for Medieval literature in a survey course, and I often just teach the Prologue to the Canterbury Tales and the Wife of Bath's Tale, which is very funny and gives students a woman's perspective.  If you have time, Sir Gawain and the Green Knight works well, in part because students recognize King Arthur and Camelot, and that seems to pique their interest.

I vote that you should keep Jane Eyre as a focal point of the Romantic era.  It just has too many great aspects of Romantic literature that you could make connections to.  I also vote for Tennyson's "Lady of Shalott" and Keats' "To Autumn" and Donne's "A Valediction Forbidding Mourning."

Covering all the high points of British literature in one semester will be impossible, as you already knew and as all the suggestions given above confirm. If there are other courses that address a specific author or period (a course that addresses specifically and only Shakespeare, for example), that would be justification for omitting that person or time from your curriculum. Students could be exposed to that material on someone else's precious class time!

Thomas Hardy is one I would want to include, and some of his novels are rather short and quite accessible, for example, The Mayor of Casterbridge and Tess of the D'Urbervilles.   On a short schedule, I'm not sure I'd want to do any Shakespeare because even one play is quite time-consuming to address properly. 

I taught British Lit on a short schedule as well.  For authors with many stories (like Chaucer), I split the class into groups and let them present to each other.  Each group (or each individual depending on the size of the class and the number of stories to be covered) reads a particular story and then presents the information they learned.  Each student is still exposed to the author but you can cover a lot more ground.  Plus, the students seemed to enjoy hearing from each other rather than always just the teacher.

It is supposed to be a survey course but I can't cover it all of course. Not sure where to focus yet but I am definitely going to do Pride & Prejudice (although I was hesitating on ruling out Jane Eyre instead).

Frankenstein is done in Humanities unfortunately :-(

Thanks for your suggestions so far! So much to look into!

I can't believe nobody has suggested a Shakespearean work! Of course, Shakespeare and British Literature go hand in hand. Especially if students don't get exposure to Shakespearean drama elsewhere, they probably should in this course. If you feel a whole play will be too time-consuming, you could always do a sonnet study as well. Teenagers seem to be able to relate to the highly emotional nature of the Shakespearean sonnet, and once they understand the metrical/rhyming pattern of sonnets, they usually find it to be pretty cool!

Speaking of poetry, I think the metaphysical poetry of John Donne is a must. It's an important contribution to literature historically, and it also provides amazing teaching opportunities for understanding and decoding metaphor/other figurative language at a sophisticated level.

I also agree with other posters--Beowulf, Sir Gawain and the Green Knight, Pride and Prejudice, and Frankenstein are all awesome Brit Lit standards. And... there's always Dickens. So many choices!

Above all, choose things that you are passionate about, that your excitement may transfer to your lucky students!

What time period are you wanting to focus on? I love British Literature and there are so many directions you could go with this! I agree with e-martin that the Romantics are probably essential. Maybe you could structure your course thematically and focus on the Victorian Age,  Romanticism, Enlightenment, etc. You could also focus on female authors such as Austen and the Bronte sisters. Wuthering Heights and Jane Eyre are two of my favorites.

I also teach Brit Lit. I begin with a historical study over the Anglo-Saxon period. After, I move into Beowulf. (Prior, I explain the kenning and students tend to love these metaphorical puzzles.) Sometimes I teach the lament and elegy poems prior to the unit ("The Seafarer," "The Wife's Lament," and "The Wanderer").

After the Anglo period, I move into the Medieval Period. Again, I give a historical overview over the period. (On a side note, these historical mini-lessons are important given they explain the background, characteristics and beliefs of the people of the period.) Once the historical background on the Medieval Period is completed, I teach Sir Gawain and the Green Knight. I heavily cover chivalry and the ideology behind the pentangle (students even create pentangles based upon Gawain's).

After the Medieval Period, I teach Chaucer (again, preteaching the historical period). The Prelude is the first thing taught. After, I typically teach The Pardoner's Tale, The Wife of Bath, and The Knight's Tale.

Lastly, I teach Frankenstein.

Chaucer, Milton and the Romantic poets (Wordsworth, Coleridge, Byron, Keats, and Blake) are fixtures in this course and can be very helpful to cover before students move on to university. 

Conrad and Austen are probably two novelists who should be included. 

I'm sure you'll get a lot of good answers here, but, to me, these are the cornerstones of an introductory Brit Lit course.