Although a switchable/dimmable 1Kw would be my choice, the OP seems to be on a budget, so like others have said, heat will be a major concern with such a lamp (even running @50%).
To get started for under $200 without having the heat issues, a Blackstar 135w UFO LED is a good choice. You can then flank with a bunch of CFLs for even more lumens.
However, that isn't much light if you veg for a long time. If you have the heat/ventilation issue covered, go with a 1000w air-cooled dimmable HID, otherwise, I'd recommend the LED.
-spek