Curly - typically it would, partly due to the overall volume and the intensity of the recovery. It's definitely feasible to combine both into a schedule.
The idea of a float is typically to maintain relaxation and turnover without forcing it, which in a shortish quality workout would likely be faster than easy pace. As you can see a verbal explanation is next to useless so in this case the best thing to do is to run it at a set, predetermined float pace.
Simon - agree on the quality late on in a run. It's good to simulate your race pace at certain points of a training run that reflect the race distance where that distance is too long for a simulation over the distance. E.g. for a 10m race 2.5m easy || 2.5m RP || 2.5m steady || 2.5m RP is a tough but doable session that has you running race pace late on in a run. It's quite a good idea to distinguish between goal pace and current race pace before the workout so you are clear what you're trying to achieve. You can also mix it up so the above might become 2.5m easy || 2.5m current race pace || 2.5m steady || 2.5m goal race pace.
Ratzer / BLF. With regards to goal setting the best starting point is to compare your improvement over previous years at a particular distance. If you knocked 2 minutes off in 2009 and 1 minute in 2010, then it's reasonably obvious what a realistic baseline should be for 2011. You can then apply some qualitative factors such as mileage etc.
It might be useful to use your basic speed as a floor. So, for 800m if your 400m time is 60 seconds and current 800m time is 2:15, the maximum possible improvement is going to be about 7 seconds unless you improve your basic speed. Equally you can use the 4 second rule to extrapolate a floor performance over longer distances.
4 Sec Rule Calc
So if you are currently converting at 6 secs then perhaps your goal could be 5 seconds etc.
Ratzer - as an aside, with a 3 year goal you do need to understand early on whether at some point it will be necessary to spend a lot of time working on basic speed or whether your goal just requires you to work on your ability to convert basic speed.
I wouldn't worry too much about the negative consequences of pushing too hard because your goal is wrong. These workouts aren't taxing to start with and are pretty short but will give enough feedback to let you know whether your goal is too tough.
Personally, I think the first thing is to schedule the period of the goal race and this would be done in conjunction with the training phases planned. So, if you allowed 6 months from start of base to peak then you'd be looking at choosing a goal in 6 months time. That actual goal is affected by so many factors that it's impossible to come up with a formula, but as experience increases it does get easier to set accurate goals. Sorry it's so vague. If anyone is going through this process it would be interesting to use it as an example.