I'm against using a hose/water on the engine bay...jap cars have a greater tendency to rust lol. Some elbow grease, common sense and patience and you can achiece much better results.
Remove air box, strut bar, valve cover..(the more the merrier lol)
1. Wire brush to remove hard surface grime/dirt buildup (use on block)
2. Spray engine degreaser safely on block, making sure not to be near sensors/connectors. Scrub down with terry cloth.
3. Bucket of water to damp the terry cloths. Wipe down using damp terry cloths.
4. Finish it off with some engine brite engine detailer to give it a nice shine, use it on hoses (spray on terry cloth and give it a wipe, give the black plastic trim some shine, the engine bay itself can come to life..)
In my opinion, hosing it down really powers out the grime/dirt you can see..which you can remove without the help of water. For those areas that the water drips down to it will just cause long term corrosion.
Example of how this can be done in an hour or so of work:
This is my '06 with 64k miles. Pervious owner never touched the engine bay. 90 minutes of work lead to these results, again, never turned on the hose!