You could get a lot done in a week!
First thing to mention is that most walking in the Lakes gets done as day walks from valley bases. It's of course possible to do longer backpacking through trips (and wild camping *is* allowed), but you don't see many folk doing this.
Accommodation in valley bases ranges from 5-star hotels, to hostels, to basic campsites. This time of year is peak season, so be prepared for places to be busy.
If at possible, I recommend you get a car, both to travel to the Lakes from wherever you're coming from, and then to get around the area. It will make your trip easier and more productive. Public transport (buses) *does* exist and is probably okay (you'll find timetables etc on the web) but getting this figured out will eat into your time. And I have no idea if you can get buses to where you might want to start walking from. I have never had much luck hitch-hiking in the Lakes, by the way: tourists generally don't want to pick up hitchers.
Guidebooks: there are *loads*. One I would recommend is 'On High Lakeland Fells' by Bob Allen. There are also plenty of web resources: just googling around now,
http://www.lakedistrictwalks.com/ looks pretty useful and even has maps.
Maps: the OS maps of the area are excellent, as is the British Mountaineering Council's 'Lake District' sheet which covers the entire area in one 1:40000 sheet. All paths are marked on the maps, so in a sense you can just chuck the guidebooks away, and make your own plans. If you're used to forcing your way through the Tasmanian scrub, then you may be pleasantly surprised to know that there are no such hazards here: most walking is across open country, and the major obstacles are in fact farmers' fences.
Specific trips: I am a little hesitant about making specific suggestions, since it definitely does depend on where you end up staying and what your transport options are. In any case, the options are virtually unlimited and anything you do will be good. However, you did ask, so:
1. I always like the feel of the north-west fells: i.e. that area west and south-west of Keswick. There, a round of Braithwaite-Grisedale Pike-HopeGill Head-Crag Hill-Sail-Causey Pike-Braithwaite is a good day out. Just to the south, the round Littletown-Robinson-Dale Head-High Spy-Littletown is also good and gives good views of Buttermere. These rounds would both be suitable if you were staying in or near Keswick.
2. For rocky scenery, the best area is the western fells: peaks like Scafell Pike, Scafell, and Great Gable. A there-and-back trip to Scafell Pike from a base in either Langdale or Borrowdale is good, but avoid weekends: Scafell Pike is the highest peak in England, and gets busy. Likewise, a trip to Great Gable from a base in Borrowdale is worth it. (If you're interested in rock climbing, Great Gable has significance, by the way: Napes Needle, on its south-west flank, is considered the birthplace of British rock-climbing.)
3. In the eastern fells, a round from Hartsop-The Knott-Kidsty Pike-Haweswater-Rough Crag-High Street-Thornthwaite Crag-Hartsop is a nice day and should be less busy. Haweswater also has interest as the only place in England where Golden Eagles are found (currently, only a solitary male, unfortunately.)
4. In the southern fells, a round from Coniston-Weatherlam-Swirl How-Coniston Old Man-Coniston is a good day out.
5. If you get sick of the crowds, head north to the hills 'back o' Skiddaw' - e.g. Carrock Fell and High Pike. The scenery here is less dramatic, but has its own attractions.
Well, I could go on (and on ...) but I hope you get the idea: there are endless possibilities.
I hope that helps a bit, or at least gives you something to think about. Post back if you have other questions. Main thing: enjoy your trip!