Yes is the straight answer.
Now the answer-a-question-with-another-couple bit:
Do you want to simply not use iPhoto at all?
Then Image Capture (in your Applications Folder) or even dragging in the Finder will do the job.
Do you still want to involve iPhoto in some way? If so,
Are you running a Managed or a Referenced Library?
A Managed Library, is the default setting, and iPhoto copies files into the iPhoto Library when Importing. The files are then stored in the Library package
A Referenced Library is when iPhoto is NOT copying the files into the iPhoto Library when importing because you made a change at iPhoto -> Preferences -> Advanced. (You unchecked the option to copy files into the Library on import) The files are then stored where ever you put them and not in the Library package. In this scenario you are responsible for the File Management.
When you plug an SD card with photos into your Mac, iPhoto will launch by default and ask if you want to import the photos into iPhoto. You can prevent the import by quitting iPhoto. You can also prevent this from happening again by going into iPhoto preferences and under General Preferences, set "Connecting camera opens" to "No Application".
Once you have deafeated iPhoto from opening, you can open a new Finder window by double clicking on the Finder in the dock and navigatiing to your SD card, which will appear with other mounted drives in the left panel of the Finder. Once you have located and selected the photos on your SD card, you can also drag and drop them to any drive in the left panel of the Finder.
On whether or not to buy Aperture: Depends entirely on the Photographer you are:
Are you a Pro? A Serious Hobbyist? Shooting Raw? Shooting High volumes (hundreds, even thousands in a shoot)? Consider Aperture
Shooting with a Phone, Shooting with a Point & Shoot, Losts of family snaps, kids parties, shooting jpeg and sharing with family and friends? iPhoto is more likely on the face of it.