For proper photoediting you basically need a monitor that's NOT based on TN technology, but one with a screen based on PVA / MVA / IPS technology. I think the lattermost IPS is the best & most common these days (detailed info at click here).
Yes, the Dell 2208WF (with a PVA-based screen) will be suitable, but where will you get one from? Or, are you thinking of buying secondhand? Dell's present & affordable IPS-based monitor is the 22" 2209WA: click here (black) & click here (silver). The 24" one is £400+.
You're right about the graphics card. Get the best CPU that falls within your budget, at least 4Gb of RAM (more if affordable) & a largish hard drive (at least 1Tb) & you'll be good to go. For more details on this, it would be best to enquire at a relevant Adobe forum click here. G