Hi 林太太,
Normally, one 火牛 is inlcuded in the package. You'll need extra 火牛 if you carry your notebook to work bewteen home and office (actually to save the loading on your shoulder!).
For the 無線上網, if you're talking about operates at home, eg, like the in houes cordless phone. Then some notebook models are included this interface already.
For the spare battery, its also depends how often you use. Forgot to remind you, normally, we use the notebook with the 火牛. We only use the battery if there is no main power supply, say travelling on bus, MTR or presentation where main power is not available. However, the battery operating time is quite limit from 2 hour to 4 or 5 depends on models also.
Should you want more detail, please raise your hand here
Franky speaking, the speed of notebook cannot compare with the desktop because of the concerns of power consumption.
I think you should consider to add more RAM (say increase up to 512Mb, or 768Mb) is more cost effective.
One more, will you use the photoshop always or very rare? For me, I still use a notebook with AMD XP processor 1400+ but with 512Mb (the maximum can be added!) to convert my draughter's DV movie into DVD video and so far so good. Because I'm not doing this always.