I think we had a large thread about this already. I argued that If you care then maybe you shouldn't answer the damn question, or look at the thread for that matter. Anyway lets not start this again. I'd more likely "flame" him because he isn't being very specific, but with a few posts his intentions have been revealed as always.
Sounds like your looking for an all purpose mic that works on most any voices that show up. I'm not sure many of these exist, and I've got to say If your gonna run a studio as your personal business and you are serious about it, I'd get quite a few of the well known mics that have specific characteristics that vary from each other greatly. Since you haven't asked that question though I'll try to answer.
MXL v69- Heard a lot of great stuff about this one, but most say its got a very loud top-end. I'm looking to buying one myself and testing this out a bit. It should sound great on a lot of vocalists, but when you get into rougher voices I think a nice dark mic would complement it. I would not recommend this for your specific needs.
Audio Technica 4050- Once again, quite a few people will recommend this one. Being relatively flat this is most likely gonna give you a strait representation of all singers. This is something I look for greatly. An other plus about this is that Its great for doubling over on quite a few stuff. I've heard over 50 people claim to having their best cab sound from the 4050. I don't know too much about it (not owning it, but will soon enough), But I can tell you I've done enough research to know its a damn good buy. There is a bit of boost above 5k, but on the cardioid pattern its really not enough to do to much besides add some clarity up top.
http://www.audio-technica.com/cms/r...f080feef8084aea/orig/at4050_freq_cardioid.jpg
AKG C-414- Now I'm not much of a fan for AKGs but I've know plenty of people who would swear by this mic. I also know plenty who would do the opposite. Personally I know nothing about it, but the AKG website may have some good stuff. Download the files for it and you'll find that its flat in all patterns, this makes me like AKG a bit more, but I like flat mics personally.
Nuemann U87- If you can get this used for 1,000, by all means go for it. Thats all I have to say.
Shure KSM-27- I own this one, and love every part about it. Great on vocals so far, especially on male voices. Very dark sounding, and great for the money. Not many people know about this one, but I happen to love it. Its really not good with bad singers I've got to say, but no mic really should be.
Studio Projects C3- Like most mics this one is relatively flat except up around 5k where a boost starts and peaks at around 10k with about a 5 db boost. Seems like It would be suitable for most anything, this may be your best bet. Heard only good about it.
Soundelux U195- Great low end response, would be great for most singers with hard voices. Good top end too, Its for the most part flat with only like +or-2 db boosts and cuts. I'd love to own one, but I dont have 1k to drop on a mic right now.
Now I know almost nothing about most of these besides a lot of forum posts and reading, and a lot of personal interest on every mic on the planet. My opinion says that the more mics you own that are different from each other the better, mostly because the more options. There really is no such thing as a bad mic (given that it works properly), and a really cheap one can be good too. I go crazy with these posts sometimes cause LDCs are my favorite part about engineering. I think I'm crazy.
Ben