Hey guys I'm looking for a lower end lens for my canon eos 450d. I'm just starting to get into photography, and I want a good lens for a general purpose lens. Money is kinda of tight so I'm looking more towards either the 18- 135mm is lens or the 18-200mm. Does any of you all have any suggestions?
You've stated money is kinda tight, but you have not stated what your budget is. If you could provide us (the community) with a budget, you will be able to receive more specific recommendations, per your general statement of wanting a good general purpose lens.
The 18-135 is $450 & the 18-200 is $595 @ B&H, so we could theoretically draw a budget based on the retail pricing of said lenses. Working within say a $600 budget, you can get a bit of lens for the $$$.
First lens I will recommend is the Tamron 17-50/2.8 Non-VC. If you are open to buying 2nd Hand, from either KEH or from the Photo Forum's B&S Boards, you can save quite a few $$$'s and get more bang for your buck. The 17-50/2.8 Non-VC averages around $350 on the used market, $450 New.
Second lens, that I will suggest, is the EF-S 55-250 IS. It can be found on the Used market for about $180 (though B&H has one for $149), or new for $255.
By splitting the Super-zoom into a couple of lenses, you will gain more in terms of IQ & flexibility. While the 18-XXX lenses sound appealing, they also create a lot of compromises. The 17-50 is a rock solid lens, that gives you both your Wide Angle but also 2.8, so you can also shoot in low light situations, whereas a 3.5-5.6 lens will typically not be the best option. And the 55-250 will still give you your reach, in the form of a telephoto.
If you have some money left over, you could invest into a Speedlite (430EX comes to mind), and start using a flash for fill & get some basic understanding about lighting. The built-in PUF is limited, and thus limits what you can do in terms of properly lighting a scene.